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• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
  • C12N1/00—Microorganisms, e.g. protozoa; Compositions thereof; Processes of propagating, maintaining or preserving microorganisms or compositions thereof; Processes of preparing or isolating a composition containing a microorganism; Culture media therefor
  • C12N1/12—Unicellular algae; Culture media therefor
• • A—HUMAN NECESSITIES
  • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
  • A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
  • A01N63/00—Biocides, pest repellants or attractants, or plant growth regulators containing microorganisms, viruses, microbial fungi, animals or substances produced by, or obtained from, microorganisms, viruses, microbial fungi or animals, e.g. enzymes or fermentates
  • A01N63/20—Bacteria; Substances produced thereby or obtained therefrom
• • A—HUMAN NECESSITIES
  • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
  • A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
  • A01N63/00—Biocides, pest repellants or attractants, or plant growth regulators containing microorganisms, viruses, microbial fungi, animals or substances produced by, or obtained from, microorganisms, viruses, microbial fungi or animals, e.g. enzymes or fermentates
  • A01N63/20—Bacteria; Substances produced thereby or obtained therefrom
  • A01N63/22—Bacillus
• • A—HUMAN NECESSITIES
  • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
  • A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
  • A01N63/00—Biocides, pest repellants or attractants, or plant growth regulators containing microorganisms, viruses, microbial fungi, animals or substances produced by, or obtained from, microorganisms, viruses, microbial fungi or animals, e.g. enzymes or fermentates
  • A01N63/50—Isolated enzymes; Isolated proteins
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K35/00—Medicinal preparations containing materials or reaction products thereof with undetermined constitution
  • A61K35/66—Microorganisms or materials therefrom
  • A61K35/74—Bacteria
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K36/00—Medicinal preparations of undetermined constitution containing material from algae, lichens, fungi or plants, or derivatives thereof, e.g. traditional herbal medicines
  • A61K36/02—Algae
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K36/00—Medicinal preparations of undetermined constitution containing material from algae, lichens, fungi or plants, or derivatives thereof, e.g. traditional herbal medicines
  • A61K36/06—Fungi, e.g. yeasts
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K14/00—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof
  • C07K14/195—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from bacteria
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
  • C12N1/00—Microorganisms, e.g. protozoa; Compositions thereof; Processes of propagating, maintaining or preserving microorganisms or compositions thereof; Processes of preparing or isolating a composition containing a microorganism; Culture media therefor
  • C12N1/14—Fungi; Culture media therefor
  • C12N1/16—Yeasts; Culture media therefor
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
  • C12N1/00—Microorganisms, e.g. protozoa; Compositions thereof; Processes of propagating, maintaining or preserving microorganisms or compositions thereof; Processes of preparing or isolating a composition containing a microorganism; Culture media therefor
  • C12N1/20—Bacteria; Culture media therefor
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
  • C12N1/00—Microorganisms, e.g. protozoa; Compositions thereof; Processes of propagating, maintaining or preserving microorganisms or compositions thereof; Processes of preparing or isolating a composition containing a microorganism; Culture media therefor
  • C12N1/38—Chemical stimulation of growth or activity by addition of chemical compounds which are not essential growth factors; Stimulation of growth by removal of a chemical compound

Definitions

• the present application is being filed along with a Sequence Listing in electronic format.
• the Sequence Listing is provided as a file entitled SEQUENCESYNG001A.TXT, created and last saved on Aug. 11, 2014, which is 380,081 bytes in size, and updated by a file entitled SYNG001C1REPLACEMENT.TXT, created and last saved on Mar. 11, 2019, which is 383,499 bytes in size.
• the information in the electronic format of the Sequence Listing is incorporated herein by reference in its entirety.
• microbial organisms Humans have used microbial organisms to generate products since the beginning of human history, for example in processing foods such as cheese, beer, and wine. During the centuries, microbial organism-mediated processes have been studied and scaled-up, often by controlling fermentation conditions or identification of phenotypic characteristics of microbial organisms.
• microbial organisms including genetically engineered microbial organisms
• feedstocks used for various industrial processes involving microorganisms are not sterile, and may contain a variety of strains and species of microorganisms.
• genetically engineered microorganisms for laboratory and pharmaceutical processes are not necessarily suited for processes, such as industrial processes, which involve using feedstocks or which are exposed to other microorganisms in the environment which could potentially contaminate the culture and which may also involve, changing environmental conditions.
• microorganisms which have been engineered to control their own growth and the growth of other microorganisms and/or to respond to changes in their environment are described. Such microorganisms are suitable for growth in non-sterile, less rigidly controlled feedstocks. Such microorganisms can be useful for robust, consistent production of a desired product across a range of different feedstocks and environments.
• Embodiments herein relate generally to the control of growth of microorganisms. More particularly, some embodiments herein relate to microorganisms engineered for regulated growth in response to other microorganisms and/or conditions of the culture environment, and methods of making and using such engineered microorganisms.
• One embodiment disclosed herein includes a first microbial cell comprising a nucleic acid encoding a secreted bacteriocin which controls the growth of a second microbial cell and a nucleic acid which confers resistance to the secreted bacteriocin is provided, in which the first microbial cell has been genetically engineered to allow the expression or activity of the nucleic acid which confers resistance to the bacteriocin to be regulated.
• the expression or activity of the nucleic acid which confers resistance to the bacteriocin is reduced to a level which causes the first microbial cell to be neutralized by the bacteriocin if the first microbial cell is released from a desired growth environment.
• the first microbial cell has been genetically engineered to make a desired product.
• the secreted bacteriocin further has been selected to maintain at least one condition within a culture in which the first microbial cell is producing the desired product.
• the culture comprises at least one invading microbial organism.
• the at least one condition of the culture comprises controlling the growth of the second microbial cell, wherein the second microbial cell is a common contaminate of the culture.
• the second microbial cell is a different strain, species or genus than the first microbial cell.
• the microbial cell further comprises a nucleic acid encoding a second secreted bacteriocin which controls the growth of a third microbial cell and a nucleic acid which confers resistance to the secreted second bacteriocin, and also the first microbial cell has been genetically engineered to allow the expression or activity of the nucleic acid which confers resistance to the bacteriocin to be regulated.
• the bacteriocin kills the second microbial cell.
• the bacteriocin reduces the growth rate of the second microbial cell.
• the bacteriocin arrests the growth of the second microbial cell.
• the transcription of the nucleic acid conferring resistance to the bacteriocin is under the control of a regulatable promoter.
• the activity of a polypeptide encoded by the nucleic acid conferring resistance to the bacteriocin is regulatable.
• the nucleic acid encoding the bacteriocin is on a chromosome of the microbial cell.
• the nucleic acid conferring resistance to the bacteriocin is on a plasmid.
• the nucleic acid encoding the bacteriocin is on a chromosome of the microbial cell, and the nucleic acid conferring resistance to the bacteriocin is on a plasmid.
• the nucleic acid encoding the bacteriocin and the nucleic acid conferring resistance to the bacteriocin are on one or more plasmids.
• the first microbial cell is selected from the group consisting of bacteria, yeast, and algae, for example photosynthetic microalgae.
• Another embodiment disclosed herein includes a method of controlling the growth of a second microbial cell in a culture medium, in which the method includes comprising culturing a first microbial cell as described herein in a culture medium comprising the second microbial cell under conditions in which the first microbial cell produces a bacteriocin at a level sufficient to control the growth of the second microbial cell.
• the culture is maintained continually for at least 30 days, for example at least 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 250, 300, 350, 400, 450, or 500 days.
• the method further includes detecting at least one change in the culture medium, the change comprising a presence or increase in the levels or activity of a third microbial cell, and reengineering the first microbial cell in response to the change to produce a second bacteriocin at a level sufficient to control the growth of the third microbial cell.
• Another embodiment disclosed herein includes a method of detecting a presence, absence, or amount of a molecule in a culture.
• the method can comprise culturing a first genetically engineered microbial cell comprising a bacteriocin under the control of a genetically regulatable promoter, such that the regulatable promoter is regulated by the molecule so that either (a) the regulatable promoter drives transcription in the presence of the molecule, but not in the absence of the molecule; or (b) the regulatable promoter drives transcription in the absence of the molecule, but not in the presence of the molecule.
• the method can comprise isolating an amount of genomic nucleic acid of the first microbial cell from the culture.
• the method can comprise detecting from the amount of genomic nucleic acid, a presence, absence, or quantity of a nucleic acid sequence characteristic of the first microbial cell. According to some aspects of this embodiment, the method further includes comparing the quantity of the nucleic acid sequence characteristic of the first microbial cell to a quantity of a reference nucleic acid sequence.
• Another embodiment disclosed herein includes a genetically engineered vector comprising a nucleic acid conferring resistance to a bacteriocin, in which the expression or activity of the nucleic acid is configured to change in response to the presence, level or absence of a component of a feedstock.
• the vector further comprises a nucleic acid encoding the bacteriocin.
• the vector further comprises a nucleic acid which encodes a desired product.
• kits which can includes a plurality of strains of a genetically engineered microbial organism, in which each strain has been genetically engineered to allow the expression or activity of a nucleic acid which confers resistance to a different bacteriocin to be regulated.
• Another embodiment disclosed herein includes a method of identifying at least one bacteriocin which modulates the growth of at least one microbial cell in an industrial culture medium, in which the method includes contacting the industrial culture medium with a medium or composition comprising the at least one bacteriocin; and determining whether the at least one bacteriocin has a desired effect on the growth of the at least one microbial cell.
• the method includes contacting the industrial culture medium with at least one bacteriocin produced by a first microbial cell as described herein.
• the at least one bacteriocin produced by the first microbial cell is in a supernatant obtained from a culture comprising the first microbial cell.
• the method further includes constructing a genetically engineered microbial cell to produce at least one bacteriocin which has been determined to have a desired effect on the growth of the at least one microbial cell.
• the at least one microbial cell is an organism which is a common invader of the industrial culture medium.
• the at least one microbial cell is an organism which has newly invaded an existing industrial culture.
• the system can comprise a first environment comprising a culture medium, and a second environment comprising a second microbial organism that secretes two or more different bacteriocins, in which the second microbial organism comprises immunity modulators for each of the two or more different bacteriocins, in which the second environment is in fluid communication with the first environment, in which the second environment is physically separated from the first environment so that the second microbial organism cannot move from the second environment to the first environment, and in which the secreted two or more different bacteriocins enter the culture medium of the first environment.
• the system further comprises a first microbial organism in the culture medium, in which the first microbial organism does not secrete the two or more different bacteriocins, and in which the first microbial organism is not neutralized by any of the two or more different bacteriocins.
• the first microbial organism is non-GMO.
• the first microbial organism ferments a component of the culture medium.
• the first microbial organism decontaminates the culture medium.
• the first microbial organism conducts photosynthesis, and the photosynthesis comprises a substrate comprised by the culture medium.
• the second environment is separated from the first environment by at least one of a membrane, a mesh, a filter, or a valve that is permeable to the two or more different bacteriocins, but is not permeable to the second microbial organisms.
• the second microbial organism secretes at least 3 bacteriocins, for example at least 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 bacteriocins.
• the second environment comprises at least a third microbial organism that is different from the second microbial organism, and also secretes bacteriocins.
• the third microbial organism secretes at least 2 bacteriocins, for example at least 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 bacteriocins.
• Another embodiment disclosed herein includes a method of storing a feedstock. The method can comprise providing a feedstock, providing a first microbial organism, in which the first microbial organism secretes two or more different bacteriocins, contacting the feedstock with the bacteriocins, and storing the feedstock for a desired period of time.
• contacting the feedstock with the bacteriocins comprises contacting the feedstock with the microbial organism.
• contacting the feedstock with the bacteriocins comprises placing the microbial organism in fluid communication with the feedstock, while maintaining physical separation between the microbial organism and the feedstock, so that the bacteriocins contact the feedstock, but the microbial organism does not directly contact the feedstock.
• the separation is maintained by at least one or more of a membrane, a mesh, a filter, or a valve that is permeable to the two or more different bacteriocins, but is not permeable to the first microbial organism.
• the method further comprises fermenting the feedstock with a second microbial organism prior to or concurrently with contacting the feedstock with the bacteriocins.
• the fermentation comprises at least one of producing a desired component in the feedstock or removing an undesired component from the feedstock.
• the desired period of time comprises at least one month, for example at least one, two, three, four, five, six, seven, eight, nine, ten, eleven, or twelve months.
• the desired period of time comprises at least six months, for example six, seven, eight nine, ten, eleven, or twelve months.
• the first microbial organism secretes at least 3 bacteriocins, for example at least 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 bacteriocins.
• FIG. 1 is a flow diagram depicting options for configuring a microbial cell to control the growth of a second microbial cell according to some of the embodiments herein.
• FIG. 2A is a schematic diagram illustrating a first microbial cell controlling the growth of other microbial cells according to some of the embodiments herein.
• FIG. 2B is a schematic diagram illustrating control of the growth of a first microbial cell when the first microbial cell is no longer in a desired growth environment according to some of the embodiments herein.
• FIG. 3 is a schematic diagram illustrating a first microbial cell controlling growth of a second microbial cell and neutralizing an invading cell in a desired environment according to some of the embodiments herein.
• FIG. 4 is a schematic diagram illustrating a first microbial cell neutralizing a first invading cell with a first bacteriocin and second invading cells with a second bacteriocin in a desired environment according to some of the embodiments herein.
• FIG. 5 is a flow diagram illustrating methods of controlling the growth of at least a second microbial cell in culture according to some embodiments herein.
• FIG. 6 is a schematic diagram illustrating a system comprising a genetic guard in accordance with some embodiments herein.
• FIG. 7 is a schematic diagram illustrating a genetic guard system that can be useful for photosynthetic production in accordance with some embodiments herein.
• FIG. 8 is a flow diagram illustrating methods of producing and using bacteriocins in accordance with some embodiments herein.
• genetically engineered microbial organisms are provided.
• the microbial organisms are engineered to control the growth of the microbial population in an environment such as those employing a feedstock.
• neutralizing activity (and variations of the same root word) of bacteriocins can refer to either arrest of microbial reproduction, or cytotoxicity.
• Microbial organisms can be engineered to produce bacteriocins, which are secreted polypeptides that can neutralize microorganisms.
• microbial organisms that produce bacteriocin immunity modulators can resist certain bacteriocins.
• a first microbial organism is engineered to secrete bacteriocins.
• the particular bacteriocins are selected based on the type of microbial cell, the types of microbial cells being regulated, the composition of the culture medium, or geographic location (for example, to target particular contaminating microbial organisms associated with a particular type of culture medium and/or geographical location).
• microbial organisms that possess desired characteristics for a particular environment can produce bacteriocin immunity modulators (and thus survive in the presence of bacteriocins), while undesired other microbial organisms (for example contaminants, microbial organisms that have lost a desired characteristic or organisms which are involved in an industrial process but whose growth or production of a particular product is not desired under the prevailing conditions) fail to produce bacteriocin immunity modulators, and are thus neutralized by the bacteriocins.
• undesired other microbial organisms for example contaminants, microbial organisms that have lost a desired characteristic or organisms which are involved in an industrial process but whose growth or production of a particular product is not desired under the prevailing conditions
• genetically engineered microorganisms are provided.
• genetically engineered “microbial organism,” “microorganism,” and variations of these root terms encompasses genetic modification of any naturally-occurring species or fully synthetic prokaryotic or eukaryotic unicellular organism, as well as Archae species.
• this expression can refer to cells of bacterial species, fungal species, and algae.
• microorganisms that can be used in accordance with embodiments herein include, but are not limited to, bacteria, yeast, and algae, for example photosynthetic microalgae.
• fully synthetic microorganism genomes can be synthesized and transplanted into single microbial cells, to produce synthetic microorganisms capable of continuous self-replication (see Gibson et al. (2010), “Creation of a Bacterial Cell Controlled by a Chemically Synthesized Genome,” Science 329: 52-56, hereby incorporated by reference in its entirety).
• the microorganism is fully synthetic.
• a desired combination of genetic elements including elements that regulate gene expression, and elements encoding gene products (for example bacteriocins, immunity modulators, poison, antidote, and industrially useful molecules) can be assembled on a desired chassis into a partially or fully synthetic microorganism.
• elements that regulate gene expression for example bacteriocins, immunity modulators, poison, antidote, and industrially useful molecules
• genes encoding gene products for example bacteriocins, immunity modulators, poison, antidote, and industrially useful molecules
• Bacillus species for example Bacillus coagulans, Bacillus subtilis , and Bacillus licheniformis
• Paenibacillus species Streptomyces species, Micrococcus species, Corynebacterium species, Acetobacter species, Cyanobacteria species, Salmonella species, Rhodococcus species, Pseudomonas species, Lactobacillus species, Enterococcus species, Alcaligenes species, Klebsiella species, Paenibacillus species, Arthrobacter species, Corynebacterium species, Brevibacterium species, Thermus aquaticus, Pseudomonas stutzeri, Clostridium thermocellus
• yeast species and strains can be used in accordance with embodiments herein, and genetically modified variants, or synthetic yeast based on a “chassis” of a known species can be provided.
• Exemplary yeast with industrially applicable characteristics include, but are not limited to Saccharomyces species (for example, Saccharomyces cerevisiae, Saccharomyces bayanus, Saccharomyces boulardii ), Candida species (for example, Candida utilis, Candida krusei ), Schizosaccharomyces species (for example Schizosaccharomyces pombe, Schizosaccharomyces japonicas), Pichia or Hansenula species (for example, Pichia pastoris or Hansenula polymorpha ) species, and Brettanomyces species (for example, Brettanomyces claussenii ).
• algae species and strains can be used in accordance with embodiments herein, and genetically modified variants, or synthetic algae based on a “chassis” of a known species can be created.
• the algae comprises photosynthetic microalgae.
• bacteriocin refers to a polypeptide that is secreted by a host cell and can neutralize at least one cell other than the individual host cell in which the polypeptide is made, including cells clonally related to the host cell and other microbial cells.
• bacteriocin also encompasses a cell-free or chemically synthesized version of such a polypeptide.
• a cell that expresses a particular “immunity modulator” is immune to the neutralizing effects of a particular bacteriocin or group of bacteriocins.
• bacteriocins can neutralize a cell producing the bacteriocin and/or other microbial cells, so long as these cells do not produce an appropriate immunity modulator.
• a host cell can exert cytotoxic or growth-inhibiting effects on a plurality of other microbial organisms by secreting bacteriocins.
• a bacteriocin is produced by the translational machinery (e.g. a ribosome, etc.) of a microbial cell.
• a bacteriocin is chemically synthesized. Some bacteriocins can be derived from a polypeptide precursor.
• the polypeptide precursor can undergo cleavage (for example processing by a protease) to yield the polypeptide of the bacteriocin itself.
• a bacteriocin is produced from a precursor polypeptide.
• a bacteriocin comprises a polypeptide that has undergone post-translational modifications, for example cleavage, or the addition of one or more functional groups.
• Antibiotic refers to a metabolite, or an intermediate of a metabolic pathway which can kill or arrest the growth of at least one microbial cell.
• Some antibiotics can be produced by microbial cells, for example bacteria. Some antibiotics can be synthesized chemically. It is understood that bacteriocins are distinct from antibiotics, at least in that bacteriocins refer to gene products (which, in some embodiments, undergo additional post-translational processing) or synthetic analogs of the same, while antibiotics refer to intermediates or products of metabolic pathways or synthetic analogs of the same.
• Neutralizing activity of bacteriocins can include arrest of microbial reproduction, or cytotoxicity.
• Some bacteriocins have cytotoxic activity (e.g. “bacteriocide” effects), and thus can kill microbial organisms, for example bacteria, yeast, algae, synthetic micoorganisms, and the like.
• Some bacteriocins can inhibit the reproduction of microbial organisms (e.g. “bacteriostatic” effects), for example bacteria, yeast, algae, synthetic micoorganisms, and the like, for example by arresting the cell cycle.
• KAMORANTM chemical has been proposed to target Lactic Acid Bacteria (LAB) family bacteria (see Union Nationale des Groupements de Distillateurs D'Alcool, (2005) “Kamoran”). It is noted that phage has also been proposed to target LAB family bacteria (see U.S. Pub. No. 2010/0330041). It is noted that pesticides have been proposed to target various contaminating microbial organisms (see McBride et al., “Contamination Management in Low Cost Open Algae Ponds for Biofuels Production” Industrial Biotechnology 10: 221-227 (2014)).
• bacteriocins can provide numerous advantages over chemicals, pesticides, or phages.
• bacteriocins can avoid potentially toxic runoff or byproduct in a feedstock.
• bacteriocins can have higher efficacy against particular undesired microbial organisms than phages, chemicals, or pesticides.
• bacteriocins can be produced by microbial organisms that undergo logarithmic growth, and thus can readily be scaled-up or scaled down, whereas the scalability of phages or chemical/pesticide systems can be more limited.
• bacteriocins can allow for precise control over which organisms are neutralized and which are not, for example to avoid neutralization of industrially useful microbial organisms in the culture medium.
• phages can be difficult to produce at an industrial scale, and also can be difficult to control, in that phages can be infectious, can raise questions of gene control, and in that conservation of phages can be difficult.
• bacteriocins in accordance with some embodiments herein can comprise part of an industrial process and thus can be involved in gene containment and/or control a fermentation process via bacteriostatic activity. Additionally, the susceptibility of the microbial organisms involved in the industrial process can be tuned via immunity control.
• bacteriocins typically have a low level of toxicity for industrial applications such as human or animal food, and it is contemplated that bacteriocins in accordance with some embodiments herein are suitable for use as a food preservative, such as an additive.
• a particular neutralizing activity (e.g. cytoxicity or arrest of microbial reproduction) is selected based on the type of microbial regulation that is desired.
• microbial cells are engineered to express particular bacteriocins or combination of bacteriocins.
• microbial cells are engineered to express particular bacteriocins based on the cells being regulated. In some embodiments, for example if contaminating cells are to be killed at least one cytotoxic bacteriocin is provided.
• a bacteriocin or combination of bacteriocins which is effective against contaminants which commonly occur in a particular culture, or a particular geographic location, or a particular type of culture grown in a particular geographic location are selected.
• a bacteriocin that inhibits microbial reproduction is provided.
• many bacteriocins can have neutralizing activity against microbial organisms that typically occupy the same ecological niche as the species that produces the bacteriocin.
• a bacteriocin when a particular spectrum of bacteriocin activity is desired, is selected from a host species that occupies the same (or similar) ecological niche as the microbial organism or organisms targeted by the bacteriocin.
• one or more bacteriocin activities are selected in advance of culture growth, and one or more microbial organisms are engineered to generate a desired culture environment.
• bacteriocins may be selected based on their ability to neutralize one or more invading organisms which are likely to attempt to grow in a particular culture.
• strains A and B in an industrial environment in which strain A makes intermediate A, and strain B converts intermediate A into intermediate B, strains A and B can be engineered so that an abundance of intermediate A shifts the equilibrium to favor strain B by generating a bacteriocin activity profile such that growth of strain A is inhibited or prevented under these conditions, while a lack of intermediate A shifts the equilibrium to favor strain A by generating a bacteriocin activity profile such that growth of strain B is inhibited or prevented.
• one or more bacteriocin activities are selected based on one or more conditions of an existing culture environment.
• “neutralizer” microorganisms can be engineered to produce bacteriocins to neutralize the identified invaders.
• genetically engineered cells that produce bacteriocins are added to an existing culture to re-equilibrate the culture, for example if a growth of a particular microbial cell type in the microbial cell culture is too high.
• genetically engineered cells that produce bacteriocins are added to an existing culture to neutralize all or substantially all of the microbial cells in a culture, for example to eliminate an industrial culture in a culture environment so that a new industrial culture can be introduced to the culture environment.
• an anti-fungal activity (such as anti-yeast activity) is desired.
• a number of bacteriocins with anti-fungal activity have been identified.
• bacteriocins from Bacillus have been shown to have neutralizing activity against yeast strains (see Adetunji and Olaoye (2013) Malaysian Journal of Microbiology 9: 130-13, hereby incorporated by reference in its entirety)
• an Enterococcus faecalis peptide WLPPAGLLGRCGRWFRPWLLWLQ SGAQY KWLGNLFGLGPK, SEQ ID NO: 1
• WLPPAGLLGRCGRWFRPWLLWLQ SGAQY KWLGNLFGLGPK SEQ ID NO: 1
• bacteriocins from Pseudomonas have been shown to have neutralizing activity against fungi such as Curvularia lunata, Fusarium species, Helminthosporium species, and Biopolaris species (Shalani and Sri).
• a bacteriocin comprises at least one of botrycidin AJ1316 or alirin B1.
• bacteriocin activity in a culture of cyanobacteria is desirable.
• bacteriocins are provided to neutralize cyanobacteria.
• bacteriocins are provided to neutralize invading microbial organisms typically found in a cyanobacteria culture environment. Clusters of conserved bacteriocin polypeptides have been identified in a wide variety of cyanobacteria species. For example, at least 145 putative bacteriocin gene clusters have been identified in at least 43 cyanobacteria species, as reported in Wang et al.
• cyanobacteria bacteriocins are shown in Table 1.2, as SEQ ID NO's 420, 422, 424, 426, 428, 30, 432, 434, 436, 438, 440, 442, 444, 446, 448, and 450.
• the host cell itself is a microbial cell.
• bacteriocins neutralize cells of a different species or strain from the host cell.
• bacteriocins neutralize cells of the same species or strain as the host cell if these cells lack an appropriate immunity modulator.
• bacteriocins can mediate neutralization of both host and non-host microbial organisms, the skilled artisan will readily appreciate that a bacteriocin is distinct from poison-antidote systems (described in more detail herein), which involve an endogenous mechanism by which a host microorganism can neutralize only itself.
• bacteriocins can neutralize cells other than the cell in which they are produced (for example, bacteriocins can be selected and/or engineered to act as an ecological niche protector), while poison molecules kill only the individual cell in which they are produced (for example, to act as suicidal systems).
• bacteriocins A number of bacteriocins have been identified and characterized. Without being limited by any particular theory, exemplary bacteriocins can be classified as “class I” bacteriocins, which typically undergo post-translational modification, and “class II” bacteriocins, which are typically unmodified. Additionally, exemplary bacteriocins in each class can be categorized into various subgroups, as summarized in Table 1.1, which is adapted from Cotter, P. D. et al. “Bacteriocins—a viable alternative to antibiotics” Nature Reviews Microbiology 11: 95-105, hereby incorporated by reference in its entirety.
• bacteriocins can effect neutralization of a target microbial cell in a variety of ways.
• a bacteriocin can permeablize a cell wall, thus depolarizing the cell wall and interfering with respiration.
• bacteriocins can be used in accordance with embodiments herein. Exemplary bacteriocins are shown in Table 1.2. In some embodiments, at least one bacteriocin comprising a polypeptide sequence of Table 1.2 is provided. As shown in Table 1.2, some bacteriocins function as pairs of molecules. As such, it will be understood that unless explicitly stated otherwise, when a functional “bacteriocin” or “providing a bacteriocin,” or the like is discussed herein, functional bacteriocin pairs are included along with bacteriocins that function individually. With reference to Table 1.2, “organisms of origin” listed in parentheses indicate alternative names and/or strain information for organisms known the produce the indicated bacteriocin.
• Embodiments herein also include peptides and proteins with identity to bacteriocins described in Table 1.2.
• identity is meant to include nucleic acid or protein sequence homology or three-dimensional homology.
• a vast range of functional bacteriocins can incorporate features of bacteriocins disclosed herein, thus providing for a vast degree of identity to the bacteriocins in Table 1.2.
• a bacteriocin has at least about 50% identity, for example, at least about 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identity to any one of the polypeptides of Table 1.2.
• Percent identity may be determined using the BLAST software (Altschul, S. F., et al. (1990) “Basic local alignment search tool.” J. Mol. Biol. 215:403-410, accessible on the world wide web at blast.ncbi.nlm.nih.gov) with the default parameters.
• a polynucleotide encoding a bacteriocin as described herein is provided.
• the polynucleotide is comprised within an expression vector.
• the polynucleotide or expression vector is in a microbial cell.
• Exemplary polynucleotide sequences encoding the polypeptides of table 1.2 are indicated in table 1.2.
• SEQ ID NOs: 341 to 419 represent exemplary polynucleotides based on the reverse translation of the respective polypeptide. The skilled artisan will readily understand that more than one polynucleotide can encode a particular polypeptide.
• the genetic code is degenerate, and moreover, codon usage can vary based on the particular organism in which the gene product is being expressed.
• a polynucleotide encoding a bacteriocin is selected based on the codon usage of the organism expressing the bacteriocin.
• a polynucleotide encoding a bacteriocin is codon optimized based on the particular organism expressing the bacteriocin.
• bacteriocins in Table 1.2 are naturally-occurring, the skilled artisan will appreciate that variants of the bacteriocins of Table 1.2, naturally-occurring bacteriocins other than the bacteriocins of Table 1.2 or variants thereof, or synthetic bacteriocins can be used according to some embodiments herein. In some embodiments, such variants have enhanced or decreased levels of cytotoxic or growth inhibition activity on the same or a different microorganism or species of microorganism relative to the wild type protein. Several motifs have been recognized as characteristic of bacteriocins.
• a synthetic bacteriocin comprises an N-terminal sequence with at least about 50% identity to SEQ ID NO: 2, for example at least about 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identity to SEQ ID NO: 2.
• a synthetic bacteriocin comprises a N-terminal sequence comprising SEQ ID NO: 2. Additionally, some class IIb bacteriocins comprise a GxxxG motif. Without being limited by any particular theory, it is believed that the GxxxG motif can mediate association between helical proteins in the cell membrane, for example to facilitate bacterioncin-mediated neutralization through cell membrane interactions. As such, in some embodiments, the bacteriocin comprises a motif that facilitates interactions with the cell membrane. In some embodiments, the bacteriocin comprises a GxxxG motif. Optionally, the bacteriocin comprising a GxxxG motif can comprise a helical structure. In addition to structures described herein, “bacteriocin” as used herein also encompasses structures that have substantially the same effect on microbial cells as any of the bacteriocins explicitly provided herein.
• fusion polypeptides comprising two or more bacteriocins or portions thereof can have neutralizing activity against a broader range of microbial organisms than either individual bacteriocin.
• a hybrid bacteriocin, Ent35-MccV GKYYGNGVSCNKKGCSVDWGRAIGIIGNNSAANLATGGAAGWKSGGGASGRDIAM AIGTLSGQFVAGGIGAAAGGVAGGAIYDYASTHKPNPAMSPSGLGGTIKQKPEGIPSE AWNYAAGRLCNWSPNNLSDVCL, SEQ ID NO: 3
• displays antimicrobial activity against pathogenic Gram-positive and Gram-negative bacteria displays antimicrobial activity against pathogenic Gram-positive and Gram-negative bacteria (Acu ⁇ a et al.
• Ent35-MccV fusion bacteriocin comprises, from N-terminus to C-terminus, an N-terminal glycine, Enterocin CRL35, a linker comprising three glycines, and a C-terminal Microcin V.
• bacteriocins can comprise fusions of two or more polypeptides having bacteriocin activity.
• a fusion polypeptide of two or more bacteriocins is provided.
• the two or more bacteriocins comprise polypeptides from Table 1.2, or modifications thereof.
• the fusion polypeptide comprising of two or more bacteriocins has a broader spectrum of activity than either individual bacteriocin, for example having neutralizing activity against more microbial organisms, neutralizing activity under a broader range of environmental conditions, and/or a higher efficiency of neutralization activity.
• a fusion of two or more bacteriocins is provided, for example two, three, four, five, six, seven, eight, nine, or ten bacteriocins.
• two or more bacteriocin polypeptides are fused to each other via a covalent bond, for example a peptide linkage.
• a linker is positioned between the two bacteriocin polypeptides.
• the linker comprises one or glycines, for example about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 glycines.
• the linker is cleaved within the cell to produce the individual bacteriocins included in the fusion protein.
• a bacteriocin as provided herein is modified to provide a desired spectrum of activity relative to the unmodified bacteriocin.
• the modified bacteriocin may have enhanced or decreased activity agains the same organisms as the unmodified bacteriocin.
• the modified bacteriocin may have enhanced activity against an organism against which the unmodified bacteriocin has less activity or no activity.
• TGTTATCTCTC NETNNFAET equisimilis TTGTTACTTCA QKEITTNSEA ( Streptococcus TTACTAGTAAT TLTNEDYTK equisimilis ) TTCAAGTACA LTSEVKTIYT GTTCCAGCAC NLIQYDQTK TTGTTTACGCT NKFYVDEDK AATGAAACAA TEQYYNYD ATAACTTTGC DESIKGVYL AGAAACTCAA MKDSLNDEL AAAGAAATTA NNNNSSNYS CAACAAATTC EIINQKISEID AGAAGCAACA YVLQGNDIN TTAACCAATG NLIPSNTRVK AAGACTACAC RSADFSWIQ TAAATTAACTT RCLEEAWGY CCGAAGTAAA AISLVTLKGI AACAATTTAT INLFKAGKFE ACAAATCTGA AAAAKLASA TTCAATACGA TAGRIAGMA CCAAACAAAA ALFAFVATC AACA
• ATGAAATTGA DQNFDEDVF lactis AACACAACCA
• GACSTNTFS Streptococcus GTTACATGGT LSDYWGNN lactis
• TGGAAGAAGT GAWCTLTHE ATCTGATCAA CMAWCK
• AATTTTGATG AAGATGTATT TGGTGCGTGT AGTACTAACA CATTCTCGCTC AGTGATTACT GGGGAAATAA CGGGGCTTGG TGTACACTCA CTCATGAATG TATGGCTTGG TGTAAATAA 154 Lacticin Lantibiotic MKEKNMKK Lactococcus 155 ATGAAAGAAA 3147 A2 NDTIELQLG lactis subsp.
• AAAATATGAA KYLEDDMIE lactis AAAGAATGAC LAEGDESHG ( Streptococcus ACTATTGAATT GTTPATPAIS lactis ) ACAATTGGGA ILSAYISTNT AAATACCTTG CPTTKCTRAC AAGATGATAT GATTGAATTA GCTGAAGGGG ATGAGTCTCA TGGAGGAACA ACACCAGCAA CTCCTGCAATC TCTATTCTCAG TGCATATATTA GTACCAATAC TTGTCCAACA ACAAAATGTA CACGTGCTTG TTAA 156 Lacticin Lantibiotic MKEQNSFNL Lactococcus 157 ATGAAAGAAC 481 LQEVTESEL lactis subsp.
• AAAACTCTTTT (Lactococcin DLILGAKGG lactis AATCTTCTTCA DR) SGVIHTISHE ( Streptococcus AGAAGTGACA CNMNSWQF lactis ) GAAAGTGAAT VFTCCS TGGACCTTATT TTAGGTGCAA AAGGCGGCAG TGGAGTTATT CATACAATTTC TCATGAATGT AATATGAATA GCTGGCAATT TGTATTTACTT GCTGCTCTTAA 158 Lacticin Q Unclassified MAGFLKVV Lactococcus 159 ATGGCAGGGT QLLAKYGSK lactis TTTTAAAAGT AVQWAWAN AGTTCAATTA KGKILDWLN CTAGCTAAAT AGQAIDWV ATGGTTCTAA VSKIKQILGIK AGCTGTACAA TGGGCTTGGG CAAACAAGGG TAAGATTTTA GATTGGCTTA ATGCAGGTCA GGCTATTGAT TGGGTAGTTT CGAAAATTAA GC
• AATTAAATTTT NGGKLTFIQ cremoris AATATTGTTTC STAAGDLYY ( Streptococcus AGATGAAGAA NTNTHKYV cremoris ) CTTTCAGAAG YQQTQNAFG CTAACGGAGG AAANTIVNG AAAATTAACA WMGGAAGG TTTATTCAATC FGLHH GACAGCGGCT GGAGATTTAT ATTACAATAC TAATACACAC AAATATGTTT ACCAACAAAC TCAAAACGCT TTTGGGGCTG CTGCTAATAC CATTGTTAAT GGATGGATGG GTGGCGCTGC TGGAGGTTTC GGGTTGCACC ATTGA 170 Lactococcin-B Unclassified MKNQLNFNI Lactococcus 171 ATGAAAAATC VSDEELAEV lactis subsp.
• AATTAAATTTT NGGSLQYV cremoris AATATTGTTTC MSAGPYTW ( Streptococcus TGATGAAGAA YKDTRTGKT cremoris ) CTTGCAGAAG ICKQTIDTAS TTAATGGAGG YTFGVMAE AAGCTTGCAG GWGKTFH TATGTTATGA GTGCTGGACC ATATACTTGG TATAAAGATA CTAGAACAGG AAAAACAATA TGTAAACAGA CAATTGACAC AGCAAGTTAT ACATTTGGTG TAATGGCAGA AGGATGGGGA AAAACATTCC ACTAA 172 Lactocyclicin Q Unclassified MKLIDHLGA Lactococcus 173 ATGAAATTAA PRWAVDTIL sp.
• TATTTTTTGCT VSAATYTRP zooepidemicus TTCTTAAGTTT LDTGNITTGF ATGCTTATTTA NGYPGHVG TATTCGGAAC VDYAVPVGT ACAAACGGTA PVRAVANGT TCTGCAGCTA VKFAGNGA CTTATACTCG NHPWMLWM GCCATTAGAT AGNCVLIQH ACGGGAAATA ADGMHTGY TCACTACAGG AHLSKISVST GTTTAACGGA DSTVKQGQII TACCCTGGTC GYTGATGQ ATGTTGGAGT VTGPHLHFE CGATTATGCA MLPANPNW GTACCCGTTG QNGFSGRID GAACTCCGGT PTGYIANAP TAGAGCAGTT VFNGTTPTE GCAAATGGTA PTTPTTNLKI CAGTCAAATT YKVDDLQKI TGCAGGTAAT NGIWQVRN GGGGCTAATC NILVPTDFT ACCCATGGAT WVDNGIAA
• NCTGGTGNNN entomocidus GCGGCGTGCA GCGTGGAACT GCTG [IN WHICH NNN ANY AMINO- ACID CODING TRIPLET] 390 Curvaticin Unclassified AYPGNGVH Lactobacillus 391 GCGTATCCGG L442 CGKYSCTVD curvatus GCAACGGCGT KQTAIGNIG GCATTGCGGC NNAA AAATATAGCT GCACCGTGGA TAAACAGACC GCGATTGGCA ACATTGGCAA CAACGCGGCG 392 Divergicin class TKYYGNGV Carnobacterium 393 ACCAAATATT M35 IIa/YGN YCNSKKCW divergens ATGGCAACGG GV VDWGTAQG ( Lactobacillus CGTGTATTGC CIDVVIGQL divergens ) AACAGCAAAAAA GGGIPGKGKC AATGCTGGGT GGATTGGGGC ACCGCGCAGG GCTGCATTGA TGTGG
• bacteriocin polynucleotide refers to a polynucleotide encoding a bacteriocin.
• the host cell comprises at least one bacteriocin.
• bacteriocin immunity modulators are shown in Table 2. While the immunity modulators in Table 2 are naturally-occurring, the skilled artisan will appreciate that variants of the immunity modulators of Table 2, naturally-occurring immunity modulators other than the immunity modulators of Table 2, or synthetic immunity modulators can be used according to some embodiments herein.
• a particular immunity modulator or particular combination of immunity modulators confers immunity to a particular bacteriocin, particular class or category of bacteriocins, or particular combination of bacteriocins.
• Exemplary bacteriocins to which immunity modulators can confer immunity are identified in Table 2. While Table 2 identifies an “organism of origin” for exemplary immunity modulators, these immunity modulators can readily be expressed in other naturally-occurring, genetically modified, or synthetic microorganisms to provide a desired bacteriocin immunity activity in accordance with some embodiments herein.
• immuno modulator refers not only to structures expressly provided herein, but also to structure that have substantially the same effect as the “immunity modulator” structures described herein, including fully synthetic immunity modulators, and immunity modulators that provide immunity to bacteriocins that are functionally equivalent to the bacteriocins disclosed herein.
• Exemplary polynucleotide sequences encoding the polypeptides of Table 2 are indicated in Table 2.
• the genetic code is degenerate, and moreover, codon usage can vary based on the particular organism in which the gene product is being expressed, and as such, a particular polypeptide can be encoded by more than one polynucleotide.
• a polynucleotide encoding a bacteriocin immunity modulator is selected based on the codon usage of the organism expressing the bacteriocin immunity modulator.
• a polynucleotide encoding a bacteriocin immunity modulator is codon optimized based on the particular organism expressing the bacteriocin immunity modulator.
• a vast range of functional immunity modulators can incorporate features of immunity modulators disclosed herein, thus providing for a vast degree of identity to the immunity modulators in Table 2.
• an immunity modulator has at least about 50% identity, for example, at least about 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identity to any one of the polypeptides of Table 2.
• Poison-antidote systems which are distinct from bacteriocins, can be useful for accomplishing such containment, or for other selective growth of microbial cells.
• Exemplary poison antidote systems are described in U.S. Pat. Nos. 5,910,438, 6,180,407, 7,176,029, and 7,183,097, each of which is hereby incorporated by reference in its entirety.
• a poison-antidote system comprises a cytotoxic (poison) polypeptide, and a corresponding antitoxin (antidote) polypeptide in a single cell.
• cytotoxic proison
• antidote antitoxin
• a “poison polynucleotide” refers to a polynucleotide encoding a poison polypeptide
• an “antidote polynucleotide” refers to a polynucleotide encoding an antidote polypeptide.
• the poison polypeptide is expressed constitutively, while the antidote polypeptide is only expressed under desired conditions. In some embodiments, the poison polypeptide is only expressed under undesired conditions, while the antidote polypeptide is only expressed under desired conditions.
• a poison/antidote system is configured so that the microbial cell survives under desired environmental conditions, but dies under undesired environmental conditions.
• a poison antidote system is configured so that the microbial cell is killed if it escapes from the environment in which it is being used in an industrial process.
• a poison antidote system is configured so that the microbial cell survives when a vector (e.g. a plasmid) encoding an antidote polypeptide is present, but dies when the vector is absent.
• the poison polypeptide is encoded by a poison polynucleotide in the host genome, while the antidote polypeptide is encoded by an antidote polynucleotide on a vector (such as a plasmid or extrachromosomal array or episome or minichromosome), and as such is only expressed when the vector is present in the host cell.
• the poison polypeptide is encoded by a poison polynucleotide on a first vector, while the antidote polypeptide is encoded by an antidote polynucleotide on a second vector, and as such is only expressed when the second vector is present.
• the presence of the antidote polynucleotide depends on the presence or absence of a recombination event, for example the integration of a polynucleotide sequence encoding the antidote polynucleotide into the host genome.
• the poison and antidote polypeptide can each be expressed constitutively.
• expression of the antidote polypeptide depends on the presence or absence of a vector or a recombination event
• expression of the poison polypeptide and/or antidote polypeptide is conditional, for example so that the poison is only expressed in conditions in which the microbial cell is not desired, and/or the antidote polypeptide is only expressed in conditions in which the microbial cell is desired.
• Exemplary microbial toxin polypeptide/antitoxin polypeptide pairs that can used in poison antidote systems in conjunction with some embodiments herein include, but are not limited to RelE/RelB, CcdB/CcdA, Kis/Kid, SoK/HoK, PasB (or PasC)/PasA, PemK/PemI, Doc/Phd, MazE/MazF and ParE/ParD.
• poison polypeptides for example RelE
• many poison polypeptides are highly conserved across Gram-positive and Gram-negative bacteria and Archae, and as such, can have cytotoxic activity in a broad range of naturally occurring, genetically modified, and fully synthetic microbial cells.
• an antidote polypeptide can generally inhibit the activity of its poison polypeptide partner in a variety of host environments, and as such, poison/antidote pairs such as those described herein can readily be used in a broad range of naturally occurring, genetically modified, and fully synthetic microbial cells.
• a poison-antidote system is distinct from a bacteriocin system at least in that a poison-antidote system provides an endogenous system by which a microbial cell can kill or arrest itself, while a bacteriocin system provides an exogenous system by which a microbial cell can kill or arrest other cells. It is further noted, however, that, while a poison-antidote system cannot be used to kill or arrest cells other than the individual cell in which the poison is produced, in some embodiments, a poison-antidote system may be used along with a bacteriocin system as described herein.
• a bacteriocin system as described herein may be used to kill or arrest the growth of cells other than the bacteriocin producing cell in a culture while the poison-antidote system may be used to kill or arrest the growth of the bacteriocin producing cell should it escape from its desired environment.
• a poison-antidote system may also be used to select for bacteriocin producing cells which have been genetically engineered to express a molecule useful in an industrial process (an “industrially useful molecule”).
• expression of an antidote can be tied to expression of an industrially useful molecule or bacteriocin by placing polynucleotides encoding the bacteriocin and the industrially useful molecule, or polynucleotides encoding the bacteriocin and antidote under the control of a single promoter.
• a microbial cell encoding a bacteriocin or bacteriocin immunity modulator further comprises a poison antidote system.
• the bacteriocin system is useful for regulating growth of the microbial cell or other microbial cells within a particular environment, while the poison-antidote system is useful for containing the microbial cell within a particular environment.
• Promoters are well known in the art.
• a promoter can be used to drive the transcription of one or more genes.
• a promoter drives expression of polynucleotide encoding a desired gene product as described herein.
• a promoter drives expression of a bacteriocin polynucleotide as described herein.
• a promoter drives expression of an immunity modulator polynucleotide as described herein.
• a promoter drives expression of a bacteriocin nucleotide and an immunity modulator polynucleotide.
• a promoter drives expression of polynucleotide encoding at least one of a bacteriocin, immunity modulator, industrially useful molecule, poison molecule, or antidote molecule.
• Some promoters can drive transcription at all times (“constitutive promoters”).
• Some promoters can drive transcription under only select circumstances (“conditional promoters”), for example depending on the presence or absence of an environmental condition, chemical compound, gene product, stage of the cell cycle, or the like.
• an appropriate promoter can be selected, and placed in cis with a sequence to be expressed.
• Exemplary promoters with exemplary activities are provided in Table 3.1-3.11 herein.
• Some promoters are compatible with particular transcriptional machinery (e.g. RNA polymerases, general transcription factors, and the like).
• RNA polymerases e.g. RNA polymerases, general transcription factors, and the like.
• these promoters can readily function in microorganisms other than the identified species, for example in species with compatible endogenous transcriptional machinery, genetically modified species comprising compatible transcriptional machinery, or fully synthetic microbial organisms comprising compatible transcriptional machinery.
• the promoters of Tables 3.1-3.11 herein are publicly available from the Biobricks foundation. Per the Biobricks foundation, use of these promoters in accordance with BioBrickTM Public Agreement (BPA) is encouraged.
• BPA BioBrickTM Public Agreement
• any of the “coding” polynucleotides described herein is generally amenable to being expressed under the control of a desired promoter.
• a single “coding” polynucleotide is under the control of a single promoter.
• two or more “coding” polynucleotides are under the control of a single promoter, for example two, three, four, five, six, seven, eight, nine, or ten polynucleotides.
• a “cocktail” of different bacteriocins can be produced by a single microbial organism.
• a bacteriocin polynucleotide is under the control of a promoter.
• an immunity modulator is under the control of a promoter.
• a polynucleotide encoding a desired gene product is under the control of a promoter.
• the bacteriocin polynucleotide and the polynucleotide encoding a desired gene product are under the control of the same promoter.
• a bacteriocin polynucleotide and the polynucleotide encoding a desired gene product are under the control of different promoters.
• the immunity modulator polynucleotide and the polynucleotide encoding a desired gene product are under the control of the same promoter.
• the bacteriocin polynucleotide and the immunity modulator polynucleotide are under the control of different promoters.
• translation initiation for a particular transcript is regulated by particular sequences at or 5′ of the 5′ end of the coding sequence of a transcript.
• a coding sequence can begin with a start codon configured to pair with an initiator tRNA.
• Met a start codon
• an initiator tRNA can be engineered to bind to any desired triplet or triplets, and accordingly, triplets other than AUG can also function as start codons in certain embodiments.
• sequences near the start codon can facilitate ribosomal assembly, for example a Kozak sequence ((gcc)gccRccAUGG, SEQ ID NO: 542, in which R represents “A” or “G”) or Internal Ribosome Entry Site (IRES) in typical eukaryotic translational systems, or a Shine-Delgarno sequence (GGAGGU, SEQ ID NO: 543) in typical prokaryotic translation systems.
• a transcript comprising a “coding” polynucleotide sequence for example a bacteriocin polynucleotide or immunity modulator polynucleotide, or polynucleotide encoding a desired industrial product, comprises an appropriate start codon and translational initiation sequence.
• each polynucleotide sequence comprises an appropriate start codon and translational initiation sequence(s).
• a translational intiator tRNA is regulatable, so as to regulate initiation of translation of a bacteriocin, immunity modulator, poison molecule, antidote molecule, or industrially useful molecule.
• aureus 556 BBa_I751501 plux-cI hybrid promoter gtgttgatgctttatcaccgccagtggta 557 BBa_I751502 plux-lac hybrid promoter agtgtgtggaattgtgagcggataacaatt 558 BBa_I761011 CinR, CinL and glucose acatcttaaaagttttagtatcatattcgt controlled promotor 559 BBa_J06403 RhIR promoter repressible by tacgcaagaaaatggtttgttatagtcgaa CI 560 BBa_J102001 Reverse Lux Promoter tcttgcgtaaacctgtacgatcctacaggt 561 BBa_J64000 rhlI promoter atcctctttagtcttccccctcatgtgtg 562 BBa
• subtilis 659 BBa_K780003 Strong constitutive promoter aattgcagtaggcatgacaaatggactca for Bacillus subtilis 660 BBa_K823000 PliaG caagctttcctttataatagaatgaatga 661 BBa_K823002 PlepA tctaagctagtgtattttgcgtttaatagt 662 BBa_K823003 Pveg aatgggctcgtgtgtacaataaatgtagt
• promoters are provided by way of non-limiting example only.
• the skilled artisan will readily recognize that many variants of the above-referenced promoters, and many other promoters (including promoters isolated from naturally existing organisms, variations thereof, and fully synthetic promoters) can readily be used in accordance with some embodiments herein.
• Gene activity can be regulated to either increase or decrease activity of the gene product.
• the gene product for which activity is regulated comprises a bacteriocin, immunity modulator, industrially useful molecule, poison molecule, or antidote molecule.
• two or more of such gene products are regulated under a single gene regulation system.
• gene activity is regulated at the level of gene expression.
• gene activity is regulated at the transcriptional level, for example by activating or repressing a promoter.
• gene activity is regulated at the post-transcriptional level, for example through regulation of RNA stability.
• gene activity is regulated at the translational level, for example through regulation of initiation of translation.
• gene activity is regulated at the post-translational level, for example through regulation of polypeptide stability, post-translational modifications to the polypeptide, or binding of an inhibitor to the polypeptide.
• gene activity is increased.
• activity of at least one of a bacteriocin, immunity modulator, industrially useful molecule, poison molecule, or antidote molecule is increased.
• gene activity can be increased by directly activating gene activity, or by decreasing the activity of an inhibitor of gene activity.
• gene activity is activated by at least one of: inducing promoter activity, inhibiting a transcriptional repressor, increasing RNA stability, inhibiting a post-transcriptional inhibitor (for example, inhibiting a ribozyme or antisense oligonucleotide), inducing translation (for example, via a regulatable tRNA), making a desired post-translational modification, or inhibiting a post-translational inhibitor (for example a protease directed to a polypeptide encoded by the gene).
• a compound present in a desired environment induces a promoter.
• the presence of iron in culture medium can induce transcription by an iron-sensitive promoter as described herein.
• a compound present in a desired culture medium inhibits a transcriptional repressor.
• the presence of tetracycline in an environment can inhibit the tet repressor, and thus allow activity from the tetO promoter.
• a compound found only outside of a desired culture medium induces transcription.
• gene activity is decreased.
• gene activity can be decreased by directly inhibiting gene activity, or by decreasing the activity of an activator of gene activity.
• gene activity is reduced, but some level of activity remains. In some embodiments, gene activity is fully inhibited.
• gene activity is decreased by at least one of inhibiting promoter activity, activating a transcriptional repressor, decreasing RNA stability, activating a post-transcriptional inhibitor (for example, expressing a ribozyme or antisense oligonucleotide), inhibiting translation (for example, via a regulatable tRNA), failing to make a required post-translational modification, inactivating a polypeptide (for example by binding an inhibitor or via a polypeptide-specific protease), or failing to properly localize a polypeptide (e.g. failing to secrete a bacteriocin).
• gene activity is decreased by removing a gene from a desired location, for example by excising a gene using a FLP-FRT or cre-lox cassette, or through loss or degradation of a plasmid.
• a gene product e.g. a polypeptide
• a product produced by a gene product e.g. the product of an enzymatic reaction
• inhibits further gene activity e.g. a negative feedback loop.
• a microorganism is genetically modified to comprise nucleic acid sequence regulating the expression of, and encoding, at least one of bacteriocins, immunity modulators, industrially useful molecules, poison molecules, or antidote molecules.
• Polynucleotides can be delivered to microorganisms, and can be stably integrated into the chromosomes of these microorganisms, or can exist free of the genome, for example in a plasmid, extrachromosomal array, episome, minichromosome, or the like.
• Exemplary vectors for genetic modification of microbial cells include, but are not limited to, plasmids, viruses (including bacteriophage), and transposable elements. Additionally, it will be appreciated that entire microbial genomes comprising desired sequences can be synthesized and assembled in a cell (see, e.g. Gibson et al. (2010), Science 329: 52-56). As such, in some embodiments, a microbial genome (or portion thereof) is synthesized with desired features such as bacteriocin polynucleotide(s), and introduced into a microbial cell.
• a cassette for inserting one or more desired bacteriocin and/or immunity modulator polynucleotides into a polynucleotide sequence is provided.
• Exemplary cassettes include, but are not limited to, a Cre/lox cassette or FLP/FRT cassette.
• the cassette is positioned on a plasmid, so that a plasmid with the desired bacteriocin and/or immunity modulator combination can readily be introduced to the microbial cell.
• the cassette is positioned in the genome of the microbial cell, so that a cassette with the desired bacteriocin and/or immunity modulator combination can be introduced to the desired location.
• plasmid conjugation can be used to introduce a desired plasmid from a “donor” microbial cell to a recipient microbial cell.
• plasmid conjugation can genetically modify a recipient microbial cell by introducing a conjugation plasmid from a donor microbial cell to a recipient microbial cell.
• conjugation plasmids that comprise the same or functionally same set of replication genes typically cannot coexist in the same microbial cell.
• plasmid conjugation “reprograms” a recipient microbial cell by introducing a new conjugation plasmid to supplant another conjugation plasmid that was present in the recipient cell.
• plasmid conjugation is used to engineer (or reengineer) a microbial cell with a particular combination of one or more bacteriocins and/or immunity modulators.
• a variety of conjugation plasmids comprising different combinations of bacteriocins and/or immunity modulators is provided.
• the plasmids can comprise additional genetic elements as described herein, for example promoters, translational initiation sites, and the like.
• the variety of conjugation plasmids is provided in a collection of donor cells, so that a donor cell comprising the desired plasmid can be selected for plasmid conjugation.
• a particular combination of bacteriocins and/or immunity modulators is selected, and an appropriate donor cell is conjugated with a microbial cell of interest to introduce a conjugation plasmid comprising that combination into a recipient cell.
• the recipient cell is a “newly engineered” cell, for example to be introduced into or for initiating a culture.
• the recipient cell is a “reengineered cell,” for example to introduce a new bacteriocin (and optionally immunity modulator) activity to an existing culture that has encountered a new type of invader cell, and/or to remove a bacteriocin activity that is no longer desired in the culture.
• Microbial culture environments can comprise a wide variety of culture media, for example feedstocks.
• the selection of a particular culture medium can depend upon the desired application.
• Conditions of a culture medium include not only chemical composition, but also temperature, amounts of light, pH, CO 2 levels, and the like.
• a genetically engineered microorganism as described herein is added to a culture medium that comprises other microorganisms and at least one feedstock.
• the culture medium comprises a compound that induces the activity or expression of a bacteriocin and/or immunity modulator.
• the culture medium comprises a compound that represses the activity or expression of a bacteriocin and/or immunity modulator.
• a compound that induces the activity of the bacteriocin is present outside of the feedstock, but not in the feedstock.
• a compound that represses the activity of the immunity modulator is present outside the feedstock, but not in the feedstock.
• feedstock is used herein in a broad sense to encompass material that can be consumed, fermented, purified, modified, or otherwise processed by microbial organisms, for example in the context of industrial processes. As such, “feedstock” is not limited to food or food products. As used herein a “feedstock” is a category of culture medium. Accordingly, as used herein “culture medium” includes, but it is not limited to feedstock. As such, whenever a “culture medium” is referred to herein, feedstocks are also expressly contemplated.
• genetically modified microbial cells are provided. Genetically modified microbial cells can be configured for a wide variety of purposes. In some embodiments, microbial cells comprise genetic modifications to regulate the expression of at least one of bacteriocins, immunity modulators, industrially useful molecules, poison molecules, or antidote molecules. In some embodiments, microbial cells comprise genetic modifications to regulate the expression of bacteriocins. In some embodiments, microbial cells comprise genetic modifications to regulate the expression of immunity modulators.
• the genetically modified microbial cells are modified to produce a product.
• the product is a gene product, for example a polypeptide or RNA.
• polynucleotide “coding” sequence as referred to herein can refer to sequence encoding either a polypeptide or an RNA.
• microbial cells can be configured to produce one or more gene products that contribute to synthesis of a desired product, for example a carbohydrate, biofuel, lipid, small molecule, or metal.
• the product is synthesized via the activity of one or more gene products of the microbial cell.
• synthesis of the product can also involve the activity of one or more gene products of one or more other microbial cells.
• microbial cells can be configured to decontaminate or decompose one or more substances in a culture media, for example a feedstock. The decontamination can be mediated wholly, or partially by one or more gene products of the microbial cells. In some embodiments, microbial cells can be configured to scavenge for a material, for example a metal such as iron or a rare earth metal.
• genetically modified microbial cells are modified to regulate the growth of other microbial cells.
• the microbial cells regulate the growth of other microbial cells of the same species or strain, for example their own clones.
• the microbial cells regulated the growth of microbial cells of a different species or strain, for example invaders.
• a microbial cell secretes a bacteriocin to regulate other microbial cells. The regulation of each of the other microbial cells can depend on its expression (or lack thereof) of an immunity modulator having protective effects against the particular the secreted bacteriocin.
• a desired cell refers to a microbial cell with at least one characteristic for which survival, growth, and/or proliferation of the microbial cell is desired, or at least an absence of negative control of the cell's growth is desired.
• a desired cell is in an appropriate environment, for example its industrially-applicable feedstock.
• a desired cell is a cell that is positively selected for, for example a cell that has undergone a particular recombination even, or is expressing high levels of a useful gene product.
• a desired cell is a cell configured to neutralize contaminating cells, for example pathogenic cells.
• a desired cell is positively selected for by its expression of an immunity modulator corresponding to at least one bacteriocin that can be present in the environment.
• an immunity modulator corresponding to at least one bacteriocin that can be present in the environment.
• a microbial cell capable of neutralizing other microbial cells which lack a similar neutralizing function will have a competitive advantage.
• a desired cell is selected for through its ability to neutralize other cells.
• a desired cell is positively selected for by expressing both a bacteriocin and a corresponding immunity modulator.
• the undesired cell refers to a microbial cell with at least one characteristic making survival, growth, or proliferation undesirable.
• the undesired cell is an invading microbial cell, for example a contaminating cell that has entered a culture environment.
• an undesired cell has escaped from an appropriate culture medium, for example its industrially-applicable feedstock.
• an undesired cell has lost a particular plasmid, or has failed to undergo a particular recombination event.
• an undesired cell has failed to produce, or produces low levels of desired gene product.
• an undesired cell is selected against.
• an undesired cell is selected against through by reducing the cell's expression or activity of an immunity modulator that protects against a bacteriocin in the environment. In some embodiments, an undesired cell is selected against through by reducing the cell's expression or activity of an immunity modulator that protects against a bacteriocin secreted by the cell and clones thereof. In some embodiments, an undesired cell is selected against by reducing the cell's expression of a bacteriocin, thereby putting the cell at a competitive disadvantage against other microbial cells.
• FIG. 1 is a flow diagram depicting options for configuring a microbial cell to control the growth of a second microbial cell according to some embodiments herein.
• a first microbial cell is provided.
• the first microbial cell secretes an active bacteriocin 100 .
• the first microbial cell is not desired 102 .
• one or more of the first microbial cell being outside its industrial environment, a desired environmental conditional for the first microbial cell being absent, the first microbial cell having made sufficient product, or the first microbial cell lacking a recombination event or vector can make the first microbial cell undesirable in a particular environment at a particular time 112 .
• the first microbial cell when the first microbial cell is not desired, its immunity modulator (corresponding to the bacteriocin) can be inactive 122 .
• an immunity modulator promoter can be inactive
• an immunity modulator transcriptional repressor can be active
• post-transcriptional silencing e.g. by a ribozyme or antisense
• a regulatable tRNA can not be induced
• post-transcriptional silencing can occur (e.g. by a site-specific protease, or a silencing post-translational modification)
• a vector encoding an immunity modulator can be absent 132 .
• the first cell when the first cell does not have an active immunity modulator, the first cell is neutralized by the bacteriocin 142 produced by other cells in the culture.
• a second microbial cell proceeds with growth 192 as a result of the first cell being neutralized.
• the first microbial cell is desired 106 .
• the first microbial cell being inside of its industrial environment, a desired environmental condition for the first microbial cell being present, the first microbial cell having not yet made sufficient product yet, or the first microbial cell having undergone a recombination event or comprising a particular vector can make the microbial cell desirable in a particular environment at a particular time 116 .
• the first microbial cell when it is desired, it can produce an active immunity modulator 126 .
• the first microbial cell can be configured to have one or more of a constitutive promoter for the immunity modulator polynucleotide, an activated (but not necessarily constitutive) promoter for the immunity modulator polynucleotide, an inactive repressor of immunity modulator transcription, a regulatable tRNA that is induced to facilitate production of the immunity modulator, an absence of post-translational and post-transcriptional silencing of the immunity modulator, or a vector encoding the immunity modulator can be present 136 .
• the first microbial cell can survive 146 in the presence of bacteriocin secreted by the first microbial cell.
• a second microbial cell can grow 192 or be neutralized 196 , depending on whether the second microbial cell has 172 or does not have 176 immunity modulator activity.
• the second microbial cell is desired 152 .
• a desired recombination event having occurred in the second microbial cell, a desired vector present in the second microbial cell, the second microbial cell producing a product of which more is desired (e.g. a positive feedback loop), or the immunity locus and the desired product being under the same transcriptional control when appropriate levels of desired product are being transcribed can a make the second microbial cell desirable 162 .
• the second microbial cell can provide immunity modulator activity to protect against the particular bacteriocin (or bacterocins) produced by the first microbial cell 172 .
• the second microbial cell can be configured such that an immunity modulator promoter is active (for example, a constitutive promoter), an immunity modulator transcriptional repressor is inactive, there is a lack of post-transcriptional silencing, a regulatable tRNA being induced to facilitate the expression of the immunity modulator, a lack of post-translational silencing (e.g. by a site-specific protease) of the immunity modulator, or a vector encoding an immunity modulator can be present 182 .
• an immunity modulator promoter for example, a constitutive promoter
• an immunity modulator transcriptional repressor is inactive
• there is a lack of post-transcriptional silencing e.g. by a site-specific protease
• a second microbial cell is not desired 156 .
• the second microbial cell being an invader (e.g. a contaminating cell), an undesired environmental condition for the second microbial cell (e.g. the presence of an undesired compound or condition, or the absence of a desired compound or condition), the second microbial cell having produced product, but no more product being desired (e.g. a negative feedback loop), or an immunity modulator locus and desired product locus being under the same transcriptional control and transcript levels being undesirably low (e.g. indicating an inability to produce a desired product) can make the second microbial cell undesirable 166 .
• an immunity modulator promoter can be inactive
• an immunity modulator transcriptional repressor can be active
• post-transcriptional silencing of the immunity modulator e.g. by a ribozyme or antisense oligonucleotide
• a regulatable tRNA can not be induced (so that expression of the immunity modulator is not facilitated)
• post-transcriptional silencing of the immunity modulator can occur (e.g.
• the first microbial cell provides secreted bacteriocin activity 100 .
• the second microbial cell can be killed by the bacteriocin 196 .
• a microbial cell controls the growth of other microbial cells in the culture.
• Exemplary functions and configurations by which a first microbial cell can control the growth of one or more other microbial cells according to some embodiments herein are described in Table 4.
• bacteriocin systems in genetically modified microbial cells according to some embodiments herein
• Exemplary Exemplary configurations Function (according to some embodiments)
• Genetic guard Bacteriocin constitutively produced genetic guard microbial organism does not produce gene products for modulating industrial process of interest
• immunity modulator constitutively produced e.g under control of constitutive promoter
• genetic guard microbial organism is insensitive to the bacteriocin (e.g. a S.
• Desired recombination event recombinants causes an immunity modulator to be restored in a bacteriocin-expressing host. Alternatively the immunity modulator can be restored only after the desired recombination event.
• Vector stability Immunity modulator (or at least one gene essential for immunity is encoded on a plasmid, and a corresponding bacteriocin locus is encoded on chromosome); clones that lose the desired plasmid lack immunity and are neutralized by the bacteriocin Minimization of Immunity modulator activity genetic drift dependent on production of industrial product (e.g.
• Immunity modulator expression controlled by an operon, in which a repressor is active in the absence of industrial product, and inactive in the presence of industrial product); if a mutation causes the microbial organism's production of industrial product to fall below a desired level or cease, the microbial organism ceases to produce immunity modulator, and is neutralized by the bacteriocin.
• Selection for Immunity modulator is microbes presenting co-expressed with the gene of a high yield interest; microbial organisms of expression producing high levels of expression (and/or gene product of interest can expressing be selected by increasing clones) bacteriocin concentration; microbial organisms producing low levels of gene product of interest (e.g.
• bacteriocins neutralize invading microbial cells
• Desired microbial cells express at least one type of bacteriocin when in the desired environment (e.g.
• bacteriocin is under the control of an inducible promoter that is activated by an intermediate of the fermentation process); secreted bacteriocins neutralize contaminating cells Control of the Immunity modulator activity ratio of a is repressed by accumulated microbial flora, product made by a microbial cell; bacteriocins secreted by the microbial cell (or other cells) neutralize the microbial cell
• FIG. 2 is a schematic diagram depicting a genetically engineered microbial cell controlling the growth of at least one other microbial cell according to some embodiments herein.
• a first microbial cell 200 can comprise a bacteriocin polynucleotide and a corresponding immunity modulator polynucleotide.
• the bacteriocin polynucleotide can optionally be integrated into the cell's genome, while the immunity modulator polynucleotide can optionally be integrated into a plasmid present in the cell.
• an undesired clone of the cell 210 (a “non-expressing clone”) can lack immunity modulator activity, and optionally can lack bacteriocin activity.
• the bacteriocin activity of the first microbial cell 200 can neutralize the non-expressing clone 210 .
• an undesired clone of the cell 220 can lose a plasmid comprising the immunity modulator polynucleotide.
• the bacteriocin activity of the first microbial cell 200 can neutralize the undesired clone 220 .
• the microbial cell 230 can escape from the desired environment, causing the clone to lack immunity modulator activity. Bacteriocin activity from the escaped cell 230 and/or clones of the escaped cell can neutralize the escaped cell 230 .
• the escaped cell 230 further comprises a poison-antidote system to facilitate killing of the escaped cell upon its escape.
• FIG. 3 is a schematic diagram of a first genetically engineered microbial cell 300 controlling the growth of a second genetically engineered microbial cell 310 and an invader cell 320 in a desired environment according to some embodiments herein.
• the first genetically engineered microbial cell 300 can comprise a first bacteriocin polynucleotide.
• the second genetically engineered microbial cell 310 can comprise a second bacteriocin polynucleotide.
• Each of the first and second genetically engineered microbial cells can comprise a first immunity modulator polynucleotide encoding resistance to the first bacteriocin, and a second immunity modulator polynucleotide encoding resistance to the second bacteriocin. If the second genetically engineered microbial cell 310 becomes undesired, it can lose first immunity modulator activity via any of the mechanisms discussed herein, and thus be controlled by the first bacteriocin activity from the first genetically engineered microbial cell 300 . If an invader cell 320 enters the desired environment, the first bacteriocin from the first genetically engineered microbial cell 300 and the second bacteriocin from the second genetically engineered microbial cell 310 can neutralize the invader cell.
• FIG. 4 is a schematic diagram of a first genetically engineered microbial cell 400 controlling the growth of a first invader cell 410 and a second invader cell 420 in a desired environment according to some embodiments herein.
• the first genetically engineered cell 400 can comprise at least a first bacteriocin polynucleotide encoding a first bacteriocin, and at least a second bacteriocin polynucleotide encoding a second bacteriocin.
• the first genetically engineered cell 400 can produce the first bacteriocin to neutralize a first invader cell 410 .
• the first genetically engineered cell 410 can produce the second bacteriocin to neutralize a second invader cell 420 .
• the first invader cell is of a different strain or species from the second invader cell. In some embodiments, the first invader cell responds to a different spectrum of bacteriocin activity than the second invader cell. In some embodiments, the first invader cell typically occupies a different ecological niche than the second invader cell.
• FIG. 5 is a flow diagram illustrating methods of controlling the growth of at least a second microbial cell in culture according to some embodiments herein.
• the method can comprise culturing a first microbial cell in a culture medium comprising a second microbial cell under conditions in which the first microbial cell produces a bacteriocin at a level sufficient to control the growth of the second microbial cell 510 .
• the culturing of the first microbial cell can optionally be continually maintained for a period of time 520 .
• the culturing of the first microbial cell is maintained continually for at least 3 days, for example at least 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 150, 200, 250, 300, 350, 400, 450, or 500 days, including ranges between any two of the listed values.
• a change in the culture medium comprising a presence or increase in the levels or activity of a third microbial cell can be detected 530 .
• the first microbial cell can be re-engineered in response to the change to produce a second bacteriocin at a level sufficient to control the growth of the third microbial cell 540 .
• the re-engineered first microbial cell can be cultured in the culture under conditions in which the first microbial cell produces a bacteriocin at a level sufficient to control the growth of the third microbial cell 550 .
• the culture of the re-engineered microbial cell can be repeated continually for a period of time 560 .
• the culturing of the re-engineered microbial cell is maintained continually for at least 3 days, for example at least 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 150, 200, 250, 300, 350, 400, 450, or 500 days, including ranges between any two of the listed values.
• a first microbial cell can control the growth of a second microbial cell. In some embodiments, a first microbial cell can control the growth of a second microbial cell of the same strain as the first microbial cell.
• Each cell of the strain can comprise a bacteriocin polynucleotide and an immunity modulator polynucleotide, such that the immunity modulator, if expressed, protects against the bacteriocin. As such, if a clone of the strain loses expression of the immunity modulator, it will be neutralized by bacteriocin activity from the same strain.
• the immunity modulator polynucleotide is in cis to the bacteriocin polynucleotide.
• the immunity modulator polynucleotide is in trans to the bacteriocin polynucleotide.
• the immunity modulator activity can be lost when the microbial cell is undesired (for example, if a plasmid is lost, or if a particular environmental condition induces a loss of immunity modulator activity). Accordingly, bacteriocin activity from both the microbial cell and also other cells of the strain can induce the neutralizing of the microbial cell.
• a ratio of two or more microbial species or strains is controlled.
• An exemplary control of ratios is illustrated in FIG. 3 (see cells 300 and 310 ).
• a first microbial strain or species loses an immunity modulator activity via any of the mechanisms discussed herein when it is less desired than a bacteriocin-producing second strain or species, increasing the ratio of second strain or species to the first strain or species.
• a bacteriostatic bacteriocin or bacteriocins are selected (as opposed to bacteriocitic bacteriocins) so that the control of growth can be readily reversible, and/or to minimize the risk of eliminating either of the strains or species.
• a first microbial strain or species produces a first bacteriocin under the control of a promoter that is activated in the presence of a compound or substance of interest, for example an intermediate or a product such as an industrially useful molecule. As such, levels of the bacteriocin increase as the levels of the compound of interest increase.
• a second microbial strain or species produces (or catalyzes the production of) the compound or substance of interest, but does not have immunity modulator activity for the bacteriocin.
• levels of the compound or substance of interest increase, levels of the bacteriocin increase, thus neutralizing the second strain (which lacks an appropriate immunity modulator or which has an insufficient amount of an appropriate immunity modulator to protect against the action of the bacteriocin).
• relative levels of the first strain compared to the second strain increase.
• a first microbial strain produces a first product and first bacteriocin activity
• a second microbial strain produces a second product and second bacteriocin activity.
• the first product and the second product are intermediates in the same biosynthetic pathway.
• the first microbial strain can provide a first and second immunity modulator activity, in which the second immunity modulator activity can protect against the second bacteriocin and is negatively regulated by accumulation of the first product (e.g. expression of the second immunity modulator is repressed by the presence of the first product), and the first immunity modulator activity can protect against the first bacteriocin.
• the second microbial strain can also provide a first and second immunity modulator activity, except that the first immunity modulator activity is negatively regulated by accumulation of the second product (e.g. expression of the first immunity modulator is repressed by the presence of the second product).
• the second immunity modulator in the first microbial strain when a relatively high amount of the first product has accumulated, the second immunity modulator in the first microbial strain is inactivated, and the microbial cells of the first strain are neutralized by the second bacteriocin, thus increasing the ratio of the second strain to the first strain, and increasing the relative amount of second product to first product.
• the first immunity modulator in the second microbial strain is inactivated, and the microbial cells of the second strain are neutralized by the first bacteriocin, the increasing the ratio of the first strain to the second strain and increasing the relative amount of first product to second product.
• the ratio of the first stain to the second strain can be adjusted, depending on relative levels of product.
• an equilibrium of ratios of the first strain to the second strain is maintained. In some embodiments, an equilibrium of ratios of the first product to the second product is maintained.
• the first microbial strain's second immunity modulator responds to a first environmental condition or compound, and the ratio between the first and second microbial strain is otherwise controlled as above. In some embodiments, the second microbial strain's first immunity modulator responds to a second environmental condition or compound, and the ratio between the first and second microbial strain is otherwise controlled as above.
• a microbial cell it is desired that a microbial cell be contained within a particular environment, for example so that the first microbial cell can only survive in a particular culture medium such as industrial feedstock.
• a microbial cell comprises a bacteriocin polynucleotide and an immunity modulator polynucleotide, such that the immunity modulator corresponds to the bacteriocin.
• the microbial cell when the microbial cell is in a desired environment, the microbial cell produces an active bacteriocin and corresponding immunity modulator, but when the microbial cell escapes the desired environment, the microbial cell produces the active bacteriocin but no active immunity modulator.
• the microbial cell can grow in the desired environment, but is neutralized by its own bacteriocin when it escapes.
• the bacteriocin encoded by the bacteriocin polynucleotide is constitutively expressed, while the immunity modulator is expressed only when the microbial cell is in a desired environment.
• the bacteriocin encoded by the bacteriocin polynucleotide is constitutively expressed, while the immunity modulator is expressed only when the microbial cell is in an environment.
• a transcriptional activator of the immunity modulator is only present in the desired environment.
• the bacteriocin encoded by the bacteriocin polynucleotide and the immunity modulator is constitutively expressed, but if the microbial cell escapes, the immunity modulator is deleted (for example via the FLP-FRT system).
• the microbial cell escapes, the immunity modulator is deleted (for example via the FLP-FRT system).
• the bacteriocin encoded by the bacteriocin polynucleotide and the immunity modulator is constitutively expressed, but if the microbial cell escapes, the immunity modulator is deleted (for example via the FLP-FRT system).
• a bacteriocin/immunity modulator system is useful both within a culture (for example, to control the growth of other genetically engineered cells in the culture, and/or to neutralize invading microbial cells), and also outside of a culture (for example, to neutralize a microbial cell that has escaped from culture), the use within the culture can provide selective pressure for the bacteriocin system to continue to function.
• Such selective pressure in accordance with some embodiments herein can minimize genetic drift.
• Such selective pressure in accordance with some embodiments herein can help to ensure that if the microbial cell escapes from the desired culture environment, the bacteriocin/immunity modulator system will be functioning to appropriately neutralize the escaped cell.
• a single genetically engineered circuit for example a bacteriocin/immunity modulator system is useful both to neutralize other microbial cells within a desired culture environment, and further to neutralize a microbial cell and/or its clones upon escape from a desired culture environment. It is contemplated in accordance with some embodiments herein, any or all of the configuration of bacteriocins disclosed herein can be tuned so that upon escape from the desired culture environment, the escaping microbial organism will be neutralized by its own bacteriocins (and/or bacteriocins of its direct or indirect progeny, and/or bacteriocins of another escaped cell and/or its direct or indirect progeny).
• a microbial cell can control growth in two or more ways.
• a microbial cell can perform two or more of the functions described in Table 4.
• the microbial cell uses the same bacteriocin/immunity modulator pair for two or more different functions.
• the microbial cell uses a first bacteriocin/immunity modulator pair for a first function, and a second bacteriocin/immunity modulator pair for a second function.
• a microbial cell can express a bacteriocin which limits the growth of “non-expressing” clones that have lost immunity modulator activity in a desired environment, and can also provide containment within the desired environment by failing to express its own immunity modulator (while still expressing bacteriocin) if the microbial cell is outside of a desired environment.
• a schematic illustration of such two forms of growth regulation is illustrated in FIG. 2 .
• a first microbial cell can express a bacteriocin which limits the growth of a second microbial cell, and can also neutralize the invading cell.
• FIG. 3 A schematic illustration of such two forms of growth regulation is illustrated in FIG. 3 .
• two or more forms of growth control are provided using the same bacteriocin-immunity modulator pair.
• each form of growth control is provided using a different bacteriocin immunity modulator pair.
• a first immunity locus can be present on a plasmid that also includes a polynucleotide encoding a desired product. A clone that loses the plasmid will be neutralized by a corresponding first bacteriocin.
• a second immunity modulator polynucleotide (corresponding to a second immunity modulator) can be integrated into the genome of the microbial cell and can be silenced when the microbial cell escapes from its desired environment (for example, the second immunity modulator polypeptide can be in a FLP-FRT cassette that is excised upon escape). As such, upon escape, the microbial cell can be neutralized by the second bacteriocin.
• a microbial cell in addition to a bacteriocin and immunity modulator further comprises a poison-antidote system configured to kill or arrest the cell when it is not in a desired environment.
• an environment can comprise, or can potentially comprise, two or more different types of undesired microbial organisms.
• bacteriocins for example, by possessing different profiles of immunity modulators
• a combination of two or more bacteriocins e.g. a “cocktail” of bacteriocins
• a “cocktail” of bacteriocins can be useful for controlling the growth of two or more microbial organisms.
• a single microbial cell produces two or more different bacteriocins for example, at least 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 35, 40, 45, or 50 different bacteriocins, including ranges between any two of the listed values.
• a mixture of two or more different bacteriocin-producing microbial cells are provided, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 35, 40, 45, or 50 different bacteriocin-producing microbial cells, including ranges between any two of the listed values.
• one or more of the bacteriocin-producing microbial cells can produce two or more different bacteriocins.
• a microbial cell can regulate the growth of two or more different types of microbial cells.
• a first type of invading cell can be possible for a first type of invading cell to possess immunity to a first type of bacteriocin but not a second type of bacteriocin.
• a microbial cell comprises two or more bacteriocin polynucleotides, each of which encodes a different bacteriocin (see, e.g. FIG. 4 ).
• the microbial cell comprises polynucleotides encoding at least three different bacteriocins, for example at least three, four five, six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen, fifteen, sixteen, seventeen, eighteen, nineteen, twenty, or more different bacteriocins, including ranges between any two of the listed values.
• two or more bacteriocin polynucleotides are under control of a single promoter.
• each bacteriocin polynucleotide under the control of a single promoter comprises its own translational initiation site.
• each bacteriocin polynucleotide is under the control of a different promoter.
• two different bacteriocins are under the control of two different but structurally or functionally identical promoters.
• a microbial cell can control the growth of other microbial cells in its industrial environment, so as to help ensure the consistent production of an industrial product, regardless of the geographical location of the culture environment.
• certain industrial products manufactured via microbial culture may have certain characteristics that result from local microbial flora associated with a certain region (for example, Camembert cheese can have particular characteristics that result from local microbial flora in Camembert, France, or sourdough bread can have particular characteristics that result from local microbial flora in San Francisco, Calif.).
• it can be desirable to control the microbial flora in a particular feedstock, so that a consistent industrial product can be produced in a variety of geographical locations.
• a microbial cell is engineered to produce bacteriocins to neutralize invading microbial cells found in a variety of geographical locations, which can ensure more consistent industrial product characteristics for product produced in a variety of locations.
• a microbial cell designed to be used in a particular industrial process and to be grown in a first geographic location may be engineered to express one or more bacteriocins effective against one or more invading organisms commonly encountered in the first geographic location.
• a microbial cell designed to be used in the same industrial process and to be grown in a second geographic location may be engineered to express one or more bacteriocins effective against one or more invading organisms commonly encountered in the second geographic location.
• a microbial cell designed to be used in a particular industrial process and to be grown in two different geographical locations may be engineered to express on or more bacteriocins effective against one or more invading organisms commonly encountered in each of the two geographical locations.
• invading microbial strains can be fought, genetic drift can be minimized, and escape can be minimized by inducing suicidal bacteriocins based genetic circuits.
• a culture is stably maintained, at least in part, by bacteriocin-mediated neutralization of invading microbial cells.
• a culture is stably maintained, at least in part, by bacteriocin-mediated control of ratios of two or more types of genetically engineered microbial cell in the culture.
• a culture is stably maintained, at least in part, by reengineering a microbial cell already present in the culture.
• the microbial cell is reengineered to add at least one additional bacteriocin activity (for example by adding a new bacteriocin, or expanding the expression of a bacteriocin already present) to neutralize a new type of invading microbial organism.
• the microbial cell is reengineered to remove at least one bacteriocin activity that is no longer needed. Exemplary methods of maintaining a stable culture according to some embodiments herein are illustrated in FIG. 5 .
• a stable culture is maintained for at least about 3 days, for example about 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 150, 200, 250, 300, 350, 400, 450, or 500 days, including ranges between any two of the listed values.
• the ratios of two or more microbial strains or species can be controlled, depending on relative quantities of product, and/or compounds in the environment. Accordingly, in some embodiments, the ratios of the two or more microbial strains or species can be indicative of relative quantities of the product and/or compounds in the environment. In some embodiments, relative quantities of microbes of a first strain or species and second strain or species as described herein are detected, thereby indicating relative ratios or quantities of a first product or compound to a second product or compound. Relative quantities of each microbial strain or species can be detected in a variety of ways. In some embodiments, each strain or species comprises a unique oligonucleotide or polypeptide “bar code” sequence to facilitate specific detection.
• each strain or species comprises a different bacteriocin (and thus a different bacteriocin polynucleotide), which can serve as a bar code.
• at least one of quantitative PCR, oligonucleotide array analysis, flow cytometry, immunocytochemistry, in situ hybridization, ELISA, immunoblotting, oligonucleotide spot blotting, or the like is performed to determine relative quantities of the two different microbial strains or species.
• growth of microbial organisms in industrial medium is modulated.
• a particular genetically engineered microbial cell or combination of genetically engineered cells it can be useful to determine the effects, if any, of the bacteriocins on the growth of the microbial cells in the existing industrial culture.
• the effect of a particular bacteriocin or combination of bacteriocins produced by genetically engineered cells on microbial organisms is assessed.
• a medium or other composition comprising one or more bacteriocins produced by genetically engineered microbial cells as described herein can be provided.
• the medium comprises a supernatant comprising one or more bacteriocins.
• the composition comprises one or more enriched or purified bacteriocins.
• the supernatant or composition is thermally stable, for example to facilitate elimination of any microbes therein through high-temperature incubation, while retaining the function of any bacteriocins therein.
• the medium or composition comprises a lyophilized material comprising bacteriocins.
• the medium or composition comprises a substrate bound to bacteriocins, for example a gel, a matrix, or beads. The medium or compositions comprising bacteriocins can be added to the existing culture. In some embodiments, the medium or composition is added to a culture in an industrial culture environment.
• the medium or composition is contacted with a sample of a culture from an industrial culture environment.
• the growth or absence of growth of microbial organisms in the industrial culture can be assessed for example to determine whether the one or more bacteriocins are effective against a new invading organism which has appeared in the culture or to determine the effects of the one or more bacteriocins on the existing organisms in the culture.
• bacteriocins Before a genetically engineered microbial cell is produced, it can be useful to simulate the effects of one or more bacteriocins on a particular culture environment.
• a particular bacteriocin or combination of bacteriocins with desired activity in a known culture environment is identified, and a microbial cell is constructed to produce the desired bacteriocin combination of bacteriocins.
• a candidate bacteriocin or combination of bacteriocins is contacted with a portion of an industrial culture of interest, and effects of the bacteriocin or bacteriocins on microbial organisms in the culture are identified.
• a variety of bacteriocins is provided.
• the variety of bacteriocins is provided in a kit.
• the bacteriocins were produced by microbial cells.
• the bacteriocins are in supernatant from one or more microbial cells as described herein.
• the bacteriocins were chemically synthesized.
• One or more candidate bacteriocins or mixtures of bacteriocins can be prepared, and can be contacted with a portion of the industrial culture environment.
• one or more bacteriocins are added to the supernatant of a bacteriocin-producing genetically engineered cell that is already present in culture, for example to ascertain the effects of engineering the cell to produce at least one additional bacteriocin.
• a sample from the industrial culture environment is contacted with each candidate bacteriocin or mixture of bacteriocins.
• each candidate bacteriocin or mixture of bacteriocins is added to the culture environment.
• effects of each candidate bacteriocin or mixture of bacteriocins are observed, for example as effects on the growth of at least one desired microbial cell in the culture, and/or the growth of at least one undesired microbial cell in the culture.
• a microbial cell can be constructed to produce the desired combination of bacteriocins.
• an existing microbial cell for example a microbial cell that is producing a desired product or intermediate in industrial culture is reengineered to produce the desired combination of bacteriocins.
• the microbial cell is reengineered via plasmid conjugation.
• a new cell is engineered to produce the desired combination of bacteriocins and added to the industrial culture.
• a “genetic guard microbial organism” is provided (which, as a shorthand, may also be referred to herein as a “genetic guard”).
• a “genetic guard” refers to a microbial organism or collection of microbial organisms that produces one or more bacteriocins so as to protect a “protected” microbial organism that is immune to neutralizing effects of the bacteriocins, but does not itself produce the bacteriocins.
• the “protected” microbial organism can perform a desired industrial process (for example, fermentation), while, as used herein, the “genetic guard” itself does not perform the desired industrial process.
• the genetic guard microbial organisms can express and secrete one or more bacteriocins.
• the genetic guard microbial organisms can constititvely express and secrete one or more of the bacteriocins.
• the genetic guard microbial organism can be non-susceptible to the bacteriocins produced by the genetic guard, for example by producing immunity modulator(s) to the bacteriocin(s) secreted by the genetic guard, and/or by being a type of microbial organism that is not susceptible to the to the bacteriocin(s) produced by the genetic guard (e.g. if the genetic guard comprises a yeast and secretes bacteriocins that specifically neutralize particular bacteria such as lactic acid bacteria).
• the protected microbial organism produces immunity modulator(s) to the bacteriocin(s) produced by the genetic guard.
• the protected microbial organism is not susceptible to the bacteriocins produced by the genetic guard (e.g. if the protected microbial organism comprises a yeast, and the genetic guard microbial organism produces bacteriocins that specifically neutralize particular bacteria).
• the protected microbial organism is not genetically modified (“non-GMO”).
• the protected microbial organism is non-GMO, but is from a strain selected to have desired properties, for example via selective pressure, and/or classical mutagenesis.
• a genetic guard protects a protected microbial organism from undesired microbial organisms.
• non-GMO microbial organisms can be useful in a number of processes, for example food production, or purification such as water purification.
• non-GMO “protected” microbial organisms are selected based on their ability to destroy one or more contaminants (for example, known water contaminants), and a genetic guard is provided to protect the protected microbial organisms from known or potential invading undesired microbial organisms.
• systems comprising a genetic guard as described herein are provided.
• genetic guards can be separated from the “protected” microbial organism by a membrane that is permeable to bacteriocins, but not to the genetic guard microbial organisms. As such, bacteriocins produced by the genetic guard can enter a culture medium occupied by the protected microbial organisms, thus protecting the protected organisms from one or more undesired microbial organisms while the genetic guard remains separated from the microbial organism.
• the genetic guard microbial organism produces two or more different bacteriocins, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 2, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100 different bacteriocins, including ranges between any two of the listed values, for example 2 to 100, 2 to 50, 2 to 20, 2 to 10, 5 to 100, 5 to 50, 5 to 20, 5 to 10, 10 to 100, 10 to 50, 10 to 20, 20 to 100, 20 to 50, or 50 to 100 different bacteriocins.
• the genetic guard comprises a single E. coli strains, which produces 20 different bacteriocins.
• the genetic guard produces a cocktail of bacteriocins.
• the genetic guard comprises a mixture of two or more different bacteriocin-producing microbial organisms, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 2, 30, 35, 40, 45, or 50 different bacteriocin-producing microbial organisms, so as to provide a desired combination of bacteriocins.
• the genetic guard comprises a combination of 4 different E.
• the genetic guard produces a cocktail of bacteriocins that target a particular category of microbial organism, for example lactic acid bacteria.
• the genetic guard can be separated from a particular environment or culture medium, for example to maintain an industrial culture environment or feedstock free of genetically modified organisms (GMOs).
• the genetic guard is physically separated from the protected microbial organism.
• the protected microbial organism is non-GMO.
• the genetic guard is temporally separated from the protected microbial organism.
• the protected microbial organism is non-GMO.
• temporal separation in accordance with some embodiments can comprise adding the genetic guard to a culture medium to neutralize invading organisms, and subsequently adding the protected microbial organism to the culture medium.
• the genetic guard can be neutralized prior to adding the protected microbial organism, for example via bacteriocins or a poison-antidote system as described herein.
• the genetic guard can be neutralized by their own bacteriocins, for example by repressing expression of the corresponding immunity modulator or immunity modulators in the genetic guard.
• temporal separation in accordance with some embodiments can comprise culturing the protected microbial organism in a culture medium, and subsequently adding the genetic guard to the culture medium.
• the genetic guard is positioned in a first environment, and the protected microbial organism or organisms are positioned in a second environment.
• the first environment can be separated from a second environment by a membrane permeable to bacteriocins produced by the genetic guard but not the genetic guard itself.
• the membrane is not permeable to the protected microbial organism.
• the first environment is in fluid communication with the second environment.
• the first environment comprises a first chamber, tank, or pond and the second environment comprises a second chamber, tank, or pond.
• the second environment comprises an open-air environment.
• an industrial process for example fermentation, is taking place in the second environment.
• the first environment comprises a capsule positioned inside of the second environment.
• membranes are suitable for arrangements and systems in accordance with embodiments herein, so long as the membranes are permeable to bacteriocins, but not to genetic guards.
• the membrane comprises at least one of a mesh, strainer, filter, selective valve, unidirectional valve, or porous membrane.
• the membrane comprises one or more pores having a diameter smaller than the diameter of the genetic guard.
• the bacteriocins diffuse through the membrane.
• fluidic motion from the first environment to the second environment drives the movement of the bacteriocins.
• the genetic guard is selected based on known or likely undesired microbial organisms in the culture medium.
• the genetic guard is changed after a period of time. For example, in response to changes in the invading undesired microbial organisms, the genetic guard can be adjusted so that additional bacteriocins are added, and/or some bacteriocins are removed.
• an existing microbially-mediated industrial process is performed in a new location, which is characterized by one or more potential undesired microbial organisms.
• a genetic guard producing bacteriocins targeting the undesired microbial organisms can be added to the culture medium in the new location.
• the bacteriocins of the genetic guard can neutralize one or more undesired microbial organisms, if present in the culture medium.
• the genetic guard produces a cocktail of bacteriocins.
• the cocktail of bacteriocins can be collected while the genetic guard is not, and the cocktail of bacteriocins can be contacted with a culture medium of interest. As such, separation can be maintained between the culture medium and the genetic guard.
• the cocktail of bacteriocins is collected by filtering out the genetic guard.
• the cocktail of bacteriocins is collected by centrifuging to separate the genetic guard from the bacteriocins.
• the cocktail of bacteriocins is collected by neutralizing the genetic guard. In some embodiments, the cocktail is stored prior to contact with the culture medium.
• FIG. 6 is a schematic diagram illustrating a system 600 comprising a genetic guard in accordance with some embodiments herein.
• the system 600 can comprise a first environment 610 and a second environment 620 .
• the second environment 620 can comprise an inlet 622 and/or an outlet 624 .
• a fluid or culture medium to be treated, for example polluted water or feedstock can enter 626 via the inlet 622 , and exit 628 via the outlet.
• the first environment 610 can be separated from the second environment 620 by a membrane 630 that is permeable to bacteriocins, but is not permeable to genetic guard microbial organisms 640 .
• the first environment 610 can comprise genetic guard microbial organisms 640 , which produce bacteriocins that can move 650 between the first environment 610 and the second environment 620 .
• the second environment 620 can comprise protected microbial organisms 660 , which are not susceptible to the neutralizing effects of the bacteriocins produced by the genetic guard 640 .
• the protected microbial organisms 660 can be non-GMO.
• the system 600 comprises a treatment system for polluted water.
• the system comprises a second inlet 623 so that fluid to be treated enters 627 the first environment 610 before entering the second environment 620 .
• the system can comprise the second inlet 623 but not the first inlet 622 .
• the system can comprise the second inlet 623 and the first inlet 622 .
• the genetic guard microbial organisms 640 can secrete bacteriocins to neutralize invading undesired organisms 670 , 675 , while maintaining physical separation between the genetic guard microbial organisms 640 and protected microbial organisms 660 .
• FIG. 7 is a schematic diagram illustrating a genetic guard system 700 that can be useful for photosynthetic production in accordance with some embodiments herein.
• the system 700 can comprise a first environment 710 .
• the first environment 710 can comprise an inlet 715 .
• the first environment 710 and optional inlet 715 can be in fluid and gas communication with a second environment 720 .
• the first environment 710 can be separated from the second environment 720 by a membrane 730 that is permeable to bacteriocins and gas, but is not permeable to genetic guard microbial organisms 640 .
• the first environment 710 can comprise genetic guard microbial organisms 640 , which produce bacteriocins 740 that can move between the first environment 710 and the second environment 720 .
• the second environment can comprise photosynthetic microbial organisms 750 , for example photosynthetic microalgae.
• the photosynthetic microbial organisms 750 are non-GMO.
• a source of light 760 can be in optical communication with the second environment 720 . It is contemplated that the source of light 760 can comprise sunlight and/or artificial light.
• CO 2 770 can enter the second environment 720 , and can be used in combination with light from the light source 760 for photosynthetic production by the photosynthetic microbial organisms 750 .
• the CO 2 770 can enter the inlet 715 of the first environment 710 , and enter the second environment 720 through the membrane 730 .
• Bacteriocins 740 produced by the genetic guard microbial organisms 740 can enter the second environment 720 through the membrane 730 , and can neutralize undesired microbial organisms 780 , 785 in the second environment.
• the second environment can comprise an outlet 780 , and biomass 790 produced by the photosynthetic microbial organism 760 can exit the second environment 720 via the outlet 790 .
• the genetic guard microbial organisms 640 can secrete bacteriocins to neutralize invading undesired organisms 670 , 675 , while maintaining physical separation between the genetic guard microbial organisms 640 and photosynthetic microbial organisms 750 and biomass 790 .
• a feedstock for feeding animals can be harvested in the summer, and stored until winter, when it is used to feed animals.
• a feedstock may undergo an initial round of fermentation to produce a desired component in the feedstock, or to destroy or remove a desired component in the feedstock, and/or to stabilize the feedstock for storage, and the feedstock may then be preserved until it is to be consumed.
• undesired microbial organisms can contaminate a feedstock during storage, and/or consume or destroy one or more components of the feedstock.
• microbial organisms can be selected or engineered to produce glucose from cellulose in a feedstock.
• undesired microbial organisms can catabolize the glucose.
• a genetic guard is added to a feedstock so as to protect the feedstock from one or more undesired microbial organisms during storage.
• the feedstock undergoes an initial round of processing (e.g.
• the genetic guard then protects the feedstock from subsequent undesired microbial organisms.
• the genetic guard is physically separated from the feedstock by a bacteriocin-permeable membrane during fermentation and/or during storage. It is contemplated that bacteriocin-mediated neutralization of undesired microbial organisms in a feedstock in accordance with some embodiments herein can permit a feedstock to be stored stably for long periods of time. In some embodiments, the feedstock is stably stored for at least one month, for example, at least one month, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, or 24 months.
• the genetic guard is contacted with the feedstock. In some embodiments, the genetic guard is already present in the feedstock, and proliferation of the genetic guard is induced prior to or during storage so that the genetic guard produces bacteriocins to neutralize undesired microbial organisms in the feedstock.
• bacteriocin-producing microbial organisms can be prepared for use in an industrial process which is subject to, or at risk of contamination or interference by undesired microbial organisms.
• a circuit for desired production of bacteriocins is designed, nucleic acid sequences are engineered, and the circuit is assembled and introduced to a host microbial organism.
• FIG. 8 is a flow diagram illustrating methods of preparing and using bacteriocin.
• the method can comprise identifying a set of genes coding for bacteriocins targeting the undesired microbial organisms 810 .
• An approach for identifying genes in accordance with some embodiments herein comprises identifying bacteriocin genes using an electronic database, for example bactibase, accessible on the world wide web at bactibase.pfba-lab-tun.org/main.php.
• the method can comprise designing a construct for expressing a bacteriocin, comprising integrating the gene set, promoter(s), and genetic regulatory elements 820 . As such, a construct can be designed.
• Approaches for designing an appropriate construct in accordance with some embodiments herein can comprise using parts databases, for example electronic databases such as the Biobricks foundation parts database. It is contemplated herein that in accordance with some embodiments, the skilled artisan can selected desired components (including, but not limited to bacteriocin nucleotides, promoters, and genetic regulatory elements) based on their identified functions, and engineer a construct with a desired functionality based upon the identified functionality of these components. By way of example, functionalities of different possible components can be found in one or more databases, such as the Biobricks catalog. A catalog of Biobricks components is accessible on the world wide web at parts.igem.org.
• the method can comprise engineering the gene set with compatible integration sites 830 , which can allow the genes to be assembled in a desired manner and/or appropriately introduced to a desired host.
• suitable integration sites can be used, for example restriction sites, substrates for an enzymatic recombination reaction, or sequences for homologous recombination.
• the gene set is synthesized.
• a nucleic acid comprising the gene set is synthesized.
• the gene set is provided in one or more vectors such as plasmids.
• the method can comprise assembling the circuits 840 .
• the circuits can include one or more bacteriocin nucleic acids, and a suitable promoter(s) and regulatory element(s).
• a single promoter drives expression of multiple bacteriocins and optional gene products of interest.
• different bacteriocin nucleic acids are under the control of different promoters.
• a circuit is comprised in a single construct such as a plasmid.
• a circuit is comprised in two or more constructs such as plasmids.
• a nucleic acid comprising the complete circuit is synthesized.
• the circuit is assembled using conventional molecular cloning techniques, or a combination of nucleic acid synthesis and molecular cloning. Molecular cloning techniques are well known to the skilled artisan.
• the method can comprise introducing the circuits into the desired host 850 .
• Suitable hosts include, but are not limited to, naturally occurring, genetically engineered, and fully synthetic microbial organisms, including, but not limited to the exemplary microbial organisms described herein.
• the method includes performing phenotypic characterization 860 , for example strain behavior.
• a bacteriocin-producing strain can be introduced to an existing culture medium, or can be used as a starter culture for a new culture medium.
• kits are provided according to some embodiments herein.
• the kits contain at least one of bacteriocins, bacteriocin polynucleotides, immunity modulators, immunity modulator polynucleotides, other genetic elements (such as promoters, expression vectors, conjugation plasmids, and the like), genetically engineered microbial cells, and/or culture medium as described herein.
• the kits further contain packaging, and/or instructions for use of the contents therein.
• the kits comprise a variety of bacteriocins, for example for use in ascertaining the effects of a candidate bacteriocin or combination thereof on a culture environment.
• kits comprise a variety of bacteriocin polynucleotides and immunity modulator polynucleotides, for example for constructing a microbial cell with desired characteristics.
• the kits comprise a variety of donor microbial cells that comprise donor plasmids encoding a variety of combinations of at least one bacteriocin and/or at least one immunity modulator.
• a cyanobacterium comprising a biosynthetic pathway for a lipid.
• the cyanobacterium has been genetically engineered to comprise a bacteriocin polynucleotide under the control of a first promoter that is constitutively active.
• the cyanobacterium comprises an immunity modulator polynucleotide for an immunity modulator that protects against the bacteriocin, and that is under the control of a second promoter that is only active in the presence of a precursor found in an industrially useful feedstock.
• the cyanobacterium is placed in the feedstock. While it is producing lipids in the feedstock, the cyanobacterium also secretes active bacteriocin, thus neutralizing invading microorganisms. Upon escape from the feedstock, the cyanobacterium no longer possesses immunity modulator activity, but still produces bacteriocin, and thus is neutralized by the bacteriocin.
• Example 2 Protection of Bacillus , Maintenance of a Plasmid, and Neutralization Upon Escape
• a genetically engineered Bacillus cell comprising a bacteriocin polynucleotide integrated into its chromosomal genome, and a plasmid comprising an immunity modulator polynucleotide for an immunity modulator that protects against the bacteriocin as well as a polynucleotide encoding a polypeptide to be manufactured.
• the bacteriocin is under the control of a constitutive promoter.
• the immunity modulator polynucleotide is under the control of a promoter that is only active in the presence of a precursor found in the industrially useful feedstock. As such, when the Bacillus is in the feedstock, it produces the bacteriocin to kill invading microbial cells.
• Bacillus clones lose the plasmid, they become undesirable (as they no longer can produce the polypeptide to be manufactured), and as a result of also losing the immunity modulator, are killed by the bacteriocin.
• the Bacillus cell Upon escape from the feedstock, the Bacillus cell no longer possesses immunity modulator activity, but still produces bacteriocin, and thus is neutralized by the bacteriocin produced by the other genetically engineered Bacillus cells in its environment.
• a first S. cerevisiae strain comprises a bacteriocin polynucleotide under the control of a first promoter that is induced by the presence of a metabolite. As such, the bacteriocin is expressed more strongly as levels of the metabolite increase. The encoded bacteriocin arrests the S. cerevisiae cell cycle, but is bacteriostatic, not bacteriolytic.
• the first strain also comprises an immunity modulator polynucleotide for conferring immunity to the first bacteriocin under control of a promoter that is activated by a compound present only in the industrial feedstock.
• cerevisiae comprises a polynucleotide encoding an enzyme that produces the metabolite, but does not comprise a corresponding immunity modulator activity.
• the first strain produces more and more bacteriocin, thus arresting the cell cycle of the second strain, and reducing the relative amount of cells of the second strain available. Meanwhile, the first strain continues to proliferate. Accordingly, the relative ratio of the first strain to the second strain is increased, and buildup of the metabolite is reduced.
• An Acidithiobacillus ferrooxidans strain is engineered to produce stored energy from the oxidation of Fe(II) to Fe(III) in a feedstock comprising an iron source that diffuses Fe(II) into the feedstock.
• An E. coli strain is engineered to control the growth of the first strain of A. ferrooxidans .
• the A. ferroxidans strain comprises a nucleic acid encoding Colicin-Ia (SEQ ID NO: 56) under the control of a rus operon promoter (SEQ ID NO: 549), and a nucleic acid encoding a Colicin-Ia immunity modulator (SEQ ID NO: 464) under the control of a constitutive promoter ( B.
• the ferroxidans strain does not produce any Colicin-E1 immunity modulator.
• the E. coli strain comprises a nucleic acid encoding Colicin-E1 (SEQ ID NO: 54) and Colicin-E1 immunity modulator (SEQ ID NO: 465) under the control of a constitutive promoter (SEQ ID NO: 651) integrated into its genome.
• SEQ ID NO: 651 constitutive promoter
• the E. coli strain does not produce Colicin-Ia immunity modulator (SEQ ID NO: 464).
• As the A. ferroxidans oxidizes Fe(II) to Fe(III), levels of Fe(II) decrease. As such, activity of the rus promoter decreases, and the A.
• ferroxidans produces lower levels of Colicin-Ia (SEQ ID NO: 54). Accordingly, any neutralization of the E. coli strain is minimized.
• the second strain of E. coli proliferates, producing higher levels of Colicin-E1 (SEQ ID NO: 54).
• the Colicin-E1 neutralizes the A. ferroxidans , so that less A. ferroxidans is present to oxidize Fe(II) into Fe(III). Accordingly levels of Fe(II) increase again.
• the A. ferroxidans produce higher levels of Colicin-Ia (SEQ ID NO: 56), neutralizing organisms the second strain of E. coli . Accordingly, there in minimal E. coli producing Colicin-E1, and neutralization of A. ferroxidans is minimal as well.
• the A. ferroxidans proliferates, oxidizing the Fe(II) into Fe(III) and storing energy.
• a genetic guard in accordance with some embodiments herein is used to protect a non-GMO microbial organism that produces ethanol from glucose in a feedstock.
• the genetic guard comprises an E. coli strain comprising and expressing 20 different bacteriocin nucleic acids under the control of a single constitutive promoter, and as such, produces 20 different bacteriocins in approximately stoichiometric ratios. It is also contemplated that in accordance with some embodiments herein, another suitable option is to provide a genetic guard comprising five different E. coli strains, each of which comprise and express five different bacteriocins. The genetic guard is disposed in the first environment 610 of a system as illustrated in FIG. 6 .
• the bacteriocins diffuse through a porous membrane to enter the second environment.
• the porous membrane is made of porous polytetrafluoroethylene that is permeable to bacteriocins and liquid, but is not permeable to the genetic guard.
• Non-GMO fermenting S. cerevisiae are cultured in the second environment.
• the non-GMO fermenting S. cerevisiae produce ethanol from glucose in the feedstock.
• the bacteriocins from the genetic guard neutralize invading microbial organisms, preventing contamination of the feedstock and consumption of the ethanol by invading microbial organisms.
• the porous membrane maintains physical separation between the genetically-engineered genetic guard and non-GMO fermenting yeast. As such, the fermenting yeast is protected from undesired microbial organisms, while a portion of the feedstock is keep free of GMO's.
• a genetic guard in accordance with some embodiments herein is used to protect a non-GMO photosynthetic microalgae that produces biomass.
• the biomass can be suitable for a variety of downstream applications, for example extracting compounds of interest, energy, or animal feed.
• the genetic guard comprises a mixture of 50 different B. subtilis strains, each of which produces a different bacteriocin.
• the genetic guard is disposed in an aqueous first environment 710 of a system as illustrated in FIG. 7 .
• the system further comprises an aqueous second environment 720 , which contains non-GMO photosynthetic microalgae, which yield biomass.
• the first environment is separated from the second environment by a 0.5 ⁇ m fiberglass filter, so as to allow gas, liquid, and bacteriocins to pass between the first environment and second environment, while blocking bacteriocins from passing between the first environment and second environment.
• CO 2 enters the system through an inlet in the first environment, and diffuses through the first environment and second environment.
• Sunlight enters the second environment, and drives the photosynthetic microalgae to produce biomass. As a result, a high-glucose biomass is produced in the second environment.
• the 50 different bacteriocins also diffuse from the first environment to the second environment.
• the bacteriocins neutralize invading undesired microbial organisms, thus preventing contamination the biomass and preventing undesired microbial organisms from interfering with biomass production and/or catabolizing the biomass.
• Biomass is harvested from the second environment via an outlet. As such, physical separation is maintained between genetically engineered genetic guard and non-GMO photosynthetic microalgae, while neutralizing invading microorganisms in the second environment.
• a Saccharomyces cerevisiae is engineered to produce multiple bacteriocins active on Lactic Acid Bacteria (LAB).
• Leucococin C SEQ ID NO: 368)
• Diversin V41 SEQ ID NO: 74
• LAB Lactic Acid Bacteria
• Leucococin C SEQ ID NO: 368
• Diversin V41 SEQ ID NO: 74
• S. cerevisiae are not sensitive to Leucococin or Diversin V41, there is no need to integrate corresponding immunity loci into the S. cerevisiae .
• Leucococin C SEQ ID NO: 368) and Diversin V41 (SEQ ID NO: 74) are selected, and polynucleotides are encoding Leucococin C (SEQ ID NO: 369) and Diversin V41 (SEQ ID NO: 75) are provided.
• the polynucleotides encode Leucococin C (SEQ ID NO: 368) and Diversin V41 (SEQ ID NO: 74), each fused to signal peptide from yeast mating factor alpha to facilitate secretion by the S. cerevisiae .
• the polynucleotides are integrated into the genome of a single S.
• PPGK1 3-Phosphoglyceratekinase
• SEQ ID NO: 692 The transformation is performed using standard homologous recombination. It is contemplated herein that other suitable strong constitutive promoters include, but are not limited to PTEF1 (translation elongation factor) and PGAP (glycerinaldehyde-3-phosphate dehydrogenase) (a list of constitutive yeast promoters is accessible on the world wide web at parts.igem.org/Promoters/Catalog/Yeast/Constitutive). The bacteriocin activity expressed by the transformed S.
• cerevisiae is measured by inhibitory assays on LAB cultures invading the production plan. As the makeup of undesired microbial organisms invading the feedstock changes over time, S. cerevisiae strains producing additional, fewer, and/or different bacteriocins can be produced and introduced into the industrial feedstock.

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Abstract

Description